Space Sunday: dust, rockets, landers and a last image

An illustration of the dust rings near the inner planets, circling the Sun. Credit:
NASA’s Goddard Space Flight Centre / Mary Pat Hrybyk-Keith

We tend to think of the Earth orbiting around the Sun along a path largely free from debris. However, this is not strictly true. Twenty-five years ago, scientists discovered that Earth orbits the Sun along with a giant ring of dust which appears to have originated within the asteroid belt that lies between Mars and Jupiter. This belt is made up of millions of rocks of all sizes, many of which over the millennia crash into one another and grind together, producing a lot of dust. This gradually falls towards the Sun as a result of gravity – but along the way, some of it is influenced by the Earth’s gravity, becoming trapped along and either side of the Earth’s orbit, forming a ring.

Observations of Mars by NASA’s Maven orbiter have also given indications that the Red Planet could have a ring – or at least, a proto-ring – occupying its orbit, while 10 years ago, astronomers discovered a ring straddling the orbit of Venus. Now a new study reveals little Mercury has a ring of dust lying along its orbit – although by rights, it shouldn’t.

Mercury’s ring was discovered entirely by accident – ironically, those responsible for its discovery, Guillermo Stenberg and Russell Howard of Naval Research Centre in Washington, DC, were attempting to find a dust-free region that is thought to surround the Sun, created by solar energy radiating outwards from our star. The idea being that determining the size of this dust-free region would both reveal more about the nature of the Sun and the evolution of the solar system. But instead of locating this area of “empty” space, the astronomers discovered the ring sharing Mercury’s orbit.

People thought that Mercury, unlike Earth or Venus, is too small and too close to the Sun to capture a dust ring. They expected that the solar wind and magnetic forces from the Sun would blow any excess dust at Mercury’s orbit away.

– Astronomer Guillermo Stenberg

The two scientists worked with images from NASA’s STEREO solar observatory. This pair of satellites  follow highly elliptical geocentric orbits. Over time, one of them pulls farther ahead of Earth while the other falls further behind. This means that together they provide stereo images of the Sun. In studying the images from the satellites, Stenberg and Howard noticed an area of enhanced brightness along Mercury’s orbit, indicative of a dust ring being present.

The question is – how did it form? There’s no answer to this yet; as Stenberg notes, the ring shouldn’t be there, and the lesson of Venus has revealed that it’s better not to assume common factors in the formation of these rings.

This is because initially, it was assumed the ring around Venus was the result of the same gravitational forces that have created the dust ring along Earth’s orbit. However, when astrophysicists Petr Pokorny and Mark Kuchner from NASA’s Goddard Space Flight Centre attempted to use extensive computer modelling to try to reproduce a dust ring matching the one in Venus’ orbit, they were unable to do so.

As a result, the two started researching and modelling possible explanations, and in a paper published on March 12th, 2019, the two suggest that the Venusian ring is the result of a previously undiscovered group of asteroids occupying the same orbit as Venus with a 1:1 resonance (that is, they complete one orbit of the Sun for every orbit Venus makes). Further, their research suggests that the group of asteroids are the remnants of a much larger asteroid ring that existed when the solar system was born.

The asteroid themselves have yet to be located – no easy task, assuming they do exist, as the Venusian dust ring is 25.5 million km (16 million mi) deep, and  9.6 million km (6 million mi) across, and bright enough to hide larger objects within it. However, if the asteroid are discovered, they would not only confirm the theory about how the dust ring around Venus’ orbit formed, but also hold clues to how the solar system formed.

Further SLS Changes

In my previous Space Sunday report, I covered the announcement by NASA that suggested  the Space Launch System rocket might have its initial launch delayed. Now it seems the system is to undergo further changes to both its initial flights and its future development.

Planned SLS development: under the White House 2020 budget request, the Exploration Upper Stage (EUS) planned for the Block 1B variants is to be deferred. Credit: NASA

As it was originally planned, the SLS was to have been initially launched in its Block 1 configuration. This would see the vehicle use what is called the Interim Cryogenic Propulsion Stage (ICPS) as its upper stage. After that, launches would switch over to using the Block 1B version, intended to use a more powerful upper stage called the Exploration Upper Stage (EUS), being built by Boeing Aerospace.

Given issues with the development of the EUS, in late 2018 NASA announced the first two SLS launches, referred to as EM-1 and EM-2, and designed to send a Orion vehicle on a month-long trip around the Moon, the first uncrewed, the second crewed, will utilise the Block 1 version of the rocket, with flights thereafter shifting to the Block 1B rocket to undertake tasks such as launching elements of the Lunar Gateway. Now, under the Trump Administration’s 2020 budget request, it appears the introduction of the EUS is to be deferred – possibly indefinitely, with NASA ordered to carry out all initial flights using the Block 1 variant of the rocket.

The Space Launch System 2nd stage – the interim cryogenic propulsion stage (ICPS) at Kennedy Space Centre, Tuesday, March 7th, 2018. Credit: ULA

While the ICPS stage is more than sufficient to achieve the objectives established for EM-1 and EM-2, it is not powerful enough to meet all of the demandd of the proposed Lunar Gateway development. Instead, NASA is expected to supplement SLS flights to build the Gateway with the use of commercial launch vehicles, such as the United Launch Alliance Delta V, the SpaceX Falcon Heavy and  – potentially – Blue Origin’s New Glenn.

Continue reading “Space Sunday: dust, rockets, landers and a last image”


Space Sunday: capsules, rockets, hammers and stars

It might look like a model, but this is SpaceX C201 – Crew Dragon DM1 – closes on the docking adapter on the Harmony module (seen in the foreground) of the International Space Station, March 3rd, 2019. Credit: NASA

SpaceX successfully completed the first demonstration flight of the Crew Dragon Capsule on Friday, March 8th, when the vehicle returned to Earth after a visit to the International Space Station (ISS).

As I reported in my previous space Sunday article, DM1 lifted-off from Launch Complex 39A at Kennedy Space Centre on March 2nd, rendezvousing with the ISS 27 hours later, when it successfully docked with the station. It remained at the station through until Friday, March 8th. At 07:30 GMT that morning the capsule and its service module detached from the space station and moved to its own orbit ready to make a re-entry into the denser atmosphere and a splashdown in the Atlantic.

C201 docked with the ISS. Note the service module with its surface of solar cells that supply the vehicle with electrical power. Credit: NASA

This phase of the mission was regarded by SpaceX as the most critical part of the flight, and the one presenting the most risk to the vehicle. While based on Cargo Dragon, the Crew Dragon is a very different vehicle; the parachute system and backshell are new, the DM1 flight being the first time they would be used operationally. The Crew Dragon’s backshell, for example, is asymmetrical in order to accommodate the eight SuperDraco escape engines designed to get the capsule out of harm’s way in the event of a launch emergency, and which are not present in the Cargo Dragon. As SpaceX CEO commented ahead of the vehicle’s launch, this asymmetry could cause roll instability on re-entry, potentially resulting in vehicle loss.

As it turned out, after moving well clear of the ISS and positioned on a track for its eventual splashdown, C201, now separated from its service module, fired its thrusters at 12:53 GMT for a 15-minute re-entry burn. Once through the seating heat of re-entry, the craft  dropped into the denser atmosphere and passed the second of its final tests: deploying first its drogue parachute system and then the four main parachutes; in doing so, it recaptured the heyday of NASA’s Mercury, Gemini and Apollo capsules.

At 13:45 GMT, C201 splashed down in the Atlantic, close to the waiting SpaceX recovery ships. Making the return aboard the capsule was the instrument-laden flight dummy “Ripley” and a small payload from the ISS. The plushy toy used as a zero-gee indicator on the vehicle’s ascent to orbit remained aboard the ISS, where it has become a celebrity. Named “Earthie” (or “Earthy”, it’s not actually clear), the plushy has been treated to tours of the ISS, has been featured in photocalls and videos, and become something of a station mascot. It will be remaining on the ISS until the first crewed flight of the Dragon vehicle docks with the ISS later this year.

Fifty years after humans landed on the moon for the first time, America has driven a golden spike on the trail to new space exploration feat. It won’t be long before our astronaut colleagues are aboard Crew Dragon and Boeing’s Starliner vehicles, and we can’t wait.

 – NASA astronaut Anne McClain aboard the ISS, marking the depature
of Crew Dragon from the station

However, even before splashdown, NASA was indicating plans to start flying crew aboard the Crew Dragon might be subject to delay. Currently, a further flight of C201 is due in June. Again, uncrewed, it is intended to test the launch abort system. The first crewed flight is currently scheduled to follow that flight, some time in July. It will carry two astronauts up to the ISS where they will remain for several weeks. However, comments from NASA’s Aerospace Safety Advisory Panel seem to suggest the crewed demonstration flights of both Crew Dragon and Boeing’s CST-100.

There’s a lot of forward work to complete on both Crew Dragon and Boeing’s CST-100 Starliner vehicles. We’re not quite ready to put humans on either vehicle yet.

– Former astronaut Sandy Magnus, a member of NASA’s Aerospace Safety Advisory Panel

C201 is hoisted aboard the main recovery ship, its white sides scorched by the passing heat of re-entry giving it a “toasted marshmallow” look. Credit: NASA

These doubts notwithstanding, Boeing and NASA have indicated that the first uncrewed flight of the CST-100 Starliner could take place in April. Referred to as Orbital Flight Test (OFT), this mission will lift off from Florida’s Cape Canaveral Air Force Station atop a United Launch Alliance (ULA) Atlas V rocket, and follow a similar profile to that of SpaceX DM1.

NASA SLS May Face Launch Delay

We are reassessing those dates to see if that date will work, based on making sure we have the vehicle ready, and ready to go fly safely. We are assessing that date. Our launch readiness date is still 2020, and we’re doing everything within our power to make sure that we support that.

– Jody Singer, director of NASA’s Marshall Space Flight Centre,
March 5th, 2019

With this words, the director of NASA’s Marshall Space Flight Centre, responsible for overseeing the development and construction of NASA new Space Launch System super booster, suggested the maiden flight of the rocket could be subject to further delay.

Singer did not give specifics on what might cause the delay following the statement, but in October 2018, NASA’s Office of Inspector General was sharply critical of both NASA and Boeing, the prime contractor for the rocket’s massive core  stage, for problems with that element. At that time, the office concluded that the first flight of the rocket – designated EM-1 – could not take place in the first half of 2020 as had been planned, so the launch date was then moved back to the latter half of the year. October 2018 also saw NASA order Boeing to slow down work on the system’s Exploration Upper Stage (EUS). Originally scheduled to be flown on the second test launch of the SLS, NASA has opted not to fly it until the third flight of the system.

An artist’s impression of a Space Launch System / Orion combination lifting off from Kennedy Space Centre’s Pad 39B. Credit: NASA

Despite the concerns raised by Singer’s comments, the other major elements of the SLS are largely complete, including its two five-segment solid rocket boosters, upper stage and adapters, leading weight to the idea that it is the core stage that is causing problems. In the meantime, structural test articles of the vehicles, liquid hydrogen and liquid oxygen tanks will be tested in the coming months at Marshall, while the core stage is due to be transferred to NASA’s Stennis Space Centre in Mississippi for so-called “green run” testing which will see its four RS-25 engines are fired on a test stand, in late 2019 early 2020, a test that’s seen as a critical test on the road to launch readiness.

Continue reading “Space Sunday: capsules, rockets, hammers and stars”

Space Sunday: capsules, moles and underground water

Lift-off: the SpaceX Crew Dragon DM1 rises from Launch Complex 39A at Kennedy Space Centre at 07:29 UT on March 2nd, 2019. Credit: Craig Vander Galien

The last time America had a capability to launch humans into space from US soil was back when the space shuttle – more formally the Space Transportation System – was still flying. However, the last shuttle flight was concluded on July 21st, 2011, when the shuttle Atlantis, with a career spanning 25 years and 33 flights into space that clocked-up 306 days, 14 hours, 12 minutes, 43 seconds in orbit, touched down at the shuttle Landing Facility at Kennedy Space Centre, Florida.

At that time, it was expected there would be just a four-year pause between the end of STS-135, the 135th shuttle flight, and the inception of a new generation of human-rated launch systems: the Boeing CST-100 Starliner, the SpaceX Crew Dragon and NASA’s own Orion system. However, development of these vehicles has been such that almost double that amount of time has passed.

But on Saturday, March 2nd, 2019, the United States did take a major step in it trek to resume a home-grown capability to launch people into space, with the successful first orbital launch of Crew Dragon.

Crew Dragon is a human-rated, reusable capsule system developed from the highly successful SpaceX Dragon cargo capsule currently used to fly supplies and equipment to and from the International Space Station (ISS). Officially designated Crew Dragon 2, it is designed to launch atop the Falcon 9 Block 5 launcher, and will operate alongside the Cargo Dragon 2, as the backbone of SpaceX’s involvement in ISS support activities. In addition, there are plans in hand to use Crew Dragon in commercial flights to the planned Bigelow Commercial Space Station, should that come to pass.

The Crew Dragon DM-1 vehicle, designated C201 and its service module, sitting within the SpaceX Horizontal Integration Facility at Kennedy Space Centre’s Launch Complex 39A, awaiting mating to its launch vehicle, December 18th, 2018. Credit: SpaceX / NASA

Once operational. it will be capable of flying up to seven crew into space, although for ISS flights, Crew Dragon will likely fly with a maximum of four crew, as NASA would like to use the added payload mass and volume ability to carry pressurised cargo to / from the ISS. Also, NASA initially do not want to use the Crew Dragon’s Super Draco motors for anything else but a propulsive assist right before final touchdown, otherwise relying on parachutes for the majority of the descent post-mission, limiting the all-up mass the capsule can bring back.

The “high-tech” zero-gee indicator installed aboard the Dragon vehicle: a plushy toy resembling the Earth, which would float free when the vehicle reached free-fall in orbit. Credit: Elon Musk

For the first orbital flight of the system – referred to as demonstration flight 1 (DM1), the Dragon 2 launched without a human crew – although it does carry an instrumented mannequin named “Ripley” after the iconic character played by Sigourney Weaver in the Alien(s) film franchise. Also on board is a small payload from NASA which the vehicle will deliver to the ISS, and a “high-tech” zero-gee indicator intended to show people watching the launch live stream the moment the vehicle achieved orbit.

Lift-off occurred precisely on time at 07:29 GMT – there was no extended window, so a failure to meet the launch time would have seen the flight postponed until March 5th, 2019. The first stage carried the vehicle through the denser part of the atmosphere, rapidly accelerating it.

Just over 2 minutes following launch, the nine first stage Merlin engines shut down, allowing the stage to separate. This continued to cost upwards as the single, vacuum-adjusted Merlin on the second stage fired, pushing it and the attached Crew Dragon on up towards orbit.

Reaching the termination point of its flight, the Falcon’s first stage carried out a series of manoeuvres that allowed it to re-ignite three of its motors in what is referred to as the “burn back” manoeuvres, designed to orient the stage for re-entry into the denser part of the atmosphere and cushion it through that re-entry phase.

These manoeuvres are a common part of Falcon 9 flights when the first stage is to be recovered post-flight. Such was the case here when, some 10 minutes after launch, the first stage made a successful landing on the SpaceX Autonomous Drone Landing Ship Of Course I Still Love You. Minutes later, the motor on the Falcon’s upper stage shut down, and the Crew Dragon separated from the stage.

Left: the Falcon 1st stage on Of Course I Still Love You, post landing. Right: a slim crescent against the blackness on the left of the image marks where Crew Dragon has separated from the Falcon’s second stage. Credit: SpaceX

Once in orbit, the Crew Dragon tested its Draco thrusters and opened its nose cone to reveal the forward docking port as it commenced a gentle “chase” to catch the ISS, gradually raising its altitude in the process.

Docking with the station began at 10:51 GMT on Sunday, March 3rd, more than 400 km (248 mi) above the Earth’s surface north of New Zealand, 27 hours after launch. The spacecraft made an initial “soft capture” with the docking port on the station’s Harmony module, the docking mechanisms then pulled Dragon into a firm “hard capture” with the station about 10 minutes later.

The Crew Dragon approaches the International Docking Adapter on one of the airlocks at the Harmony module of the ISS, March 3rd, 2019. Note the open nose cone and exposed docking port Credit: NASA.

Prior to docking the Crew Dragon closed to a distance of 150m from the station before halting its forward motion and then backing away again to 180m, testing its ability to move away from the station in the event of a problem. Once docked, a further series of checks were performed to “safe” the vehicle, prior to the hatches between it and the ISS being opened at 13:30 GMT. As a further precaution, Russian cosmonaut Oleg Kononenko and Canadian David Saint-Jacques wore gas masks to guard against any internal leaks of gas in the capsule when they first entered. After they had carried out atmospheric readings, NASA astronaut Anne McClain joined Saint-Jacques in starting to unload more than 180 kg of cargo included in the flight.

During the unloading, Saint-Jacques knocked the “high-tech” zero gee plushy, sending it carooming around the capsule, prompting mission control to observe, “Can you tell we’re in microgravity?”

The “zero-g indicator” gets a bump from CSA astronaut David Saint-Jacques that sends it tumbling around the Crew Dragon. Credit: NASA / SpaceX

The Dragon will remain docked with the ISS through until Friday, March  8th, after which it will depart for a return to Earth, bringing a small amount of cargo with it. The capsule should splash down in the Atlantic Ocean at around 13:45 GMT that day, after a parachute descent through the atmosphere.

If all goes according to plan, the capsule used in this test (C201), will make a second uncrewed flight in June 2019, when it will be used to conduct an in-flight abort test, using its Draco motors to push it free of its Falcon 9 launcher to simulate what would happen in the event of a real booster malfunction. Following that flight, and assuming there are no further issues, the second demonstration flight (DM2) should take place in July 2019, when NASA astronauts Bob Behnken and Doug Hurley, both veterans of the space shuttle, will fly to the ISS aboard Crew Dragon C203, where they will remain for 2 weeks before making a return to Earth.

Assuming that flight (Demonstration Mission 2) is successful, Crew Dragon should then be cleared to start flying crews to and from the ISS at the end of 2019.

Continue reading “Space Sunday: capsules, moles and underground water”

Space Sunday: tourist flights, landers, moons and rovers

A dramatic shot from the tail boom camera on VSS Unity just after the tail boom has been triggered to its raised “feathered” position to commence the gentle drop back into the denser atmosphere following a flight to an altitude just shy of 90 km (56.25 mi). Credit: Virgin Galactic

On Friday, February 22nd, Virgin Galactic’s VSS Unity completed a further test flight, its second time in just over two months, and in doing so set itself a new altitude record.

The space plane was released from its WhiteKnightTwo carrier, the VSM Eve at 16:53 UT, some 45 minutes after taking off from the Mojave Air and Space Port in California. The vehicle’s hybrid rocket moor was fired for roughly one minute, pushing the Unity and its crew of three to an altitude 89.9 km (56 mi), reaching a maximum velocity of Mach 3 in the process. After a successful “feathering” manoeuvre of the vehicle’s tail boom, Unity dropped back into the denser atmosphere and glided back to a runway landing in Mojave at 17:08 UT.

The flight, delayed by two days due to high winds over the planned flight test route, marked the first time the vehicle had carried a “passenger”: Beth Moses, Virgin Galactic’s chief astronaut instructor. She made the flight with David Mackay and Mike “Sooch” Masucci, respectively the company’s chief test pilot and lead trainer pilot. All three were making their first trips into space, Moses being aboard to provide practical validation and  data on aspects of the customer cabin and spaceflight environment from the perspective of “people in the back”. Her presence on the flight was not announced until after Unity had landed.

Beth, Sooch and I just enjoyed a pretty amazing flight which was beyond anything any of us has ever experienced. It was thrilling yet smooth and nicely controlled throughout with a view at the top, of the Earth from space, which exceeded all our expectations.

– Virgin Galactic chief test pilot David Mackay

Moses also kept an eye on the flight’s special payload – four science and technology demonstration packages provided by NASA under the agency’s Flight Opportunities Programme. Three of the packages had been flown on the Unity’s previous flight in December 2018.

Virgin Galactic have refused to indicate how many more test flights will be made before SpaceShipTwo starts carrying fare-paying passengers, although the company’s founder, Sir Richard Branson has indicated he hopes to fly on the vehicle in July 2019, possibly to mark the 50th anniversary of the Apollo 11 Moon landing. Speaking ahead of the February 22nd test flight, Mike Moses, president of Virgin Galactic and husband of Beth Moses, indicated that the company is in the “heart” of their flight test regime, and the focus is on expanding the envelope of flights, including their frequency, prior to committing to commercial flights.

VSS Unity touching down at Mojave Air and Space Port. Credit: Virgin Galactic

The altitudes reached by Unity thus far (just over 80 km / 50 mi on the December 2018 flight and now 89.9 km) have caused some to call into question whether or not VSS Unity has really been in space – including Jeff Bezos, who is heading Blue Origin, Virgin Galactic’s clearest rival in the sub-orbital passenger market.

Speaking about his own company’s test programme with their New Shephard launch system, Bezos emphasised the operational difference between the reusable New Shephard rock and its crew / passenger carrying capsule and Virgin’s SpaceShipTwo. The New Shephard is specifically designed to reach altitudes of 100 km (50 mi), somewhat higher that Virgin Galactic have thus far achieved. 100 km is important, as it marks the position of the Kármán Line, considered to be the point above which where aerodynamics cease having any real influence over an aircraft’s performance, making it reliant on astronautics. Thus, it is seen by some as the boundary of space.

One of the issues that Virgin Galactic will have to address, eventually, is that they are not flying above the Kármán Line, not yet … We’ve always had as our mission that we wanted to fly above the Kármán Line, because we didn’t want there to be any asterisks next to your name about whether you’re an astronaut or not. That’s something they’re going to have to address, in my opinion.

– Jeff Bezos, New Origins founder, commenting on Virgin Galactic, February 20th, 2019

New Shephard is also in the midst of a test programme that could see it flying passengers before the end of 2019. Pictures is a text flight launch on January 23rd, 2019, the 10th test flight for the system, as captured via video. Credits: Blue Origin via CBS News

However, things are actually not that clear-cut. There is no international law defining the edge of space; for example, the United States – from which both New Shepherd and Virgin Galactic will fly (at least initially in the latter’s case) considers the boundary to be 80 km (50 mi), which Virgin Galactic can clearly exceed.

Further, Theodore von Kármán, after whom the line is named, suggested the boundary could lie anywhere between 91 km and 100 km altitude. The ambiguity is exacerbated by a proposal to set the “edge” of space in international law as the lowest perigee attainable by an orbiting space vehicle – which would place it somewhere between 130 km (81 mi) and 150 km (93 mi), somewhat beyond the capabilities of either SpaceShipTwo and New Shephard, which tends to render arguments about altitude and boundaries a little moot, particularly given the fact that whether at 80-90 km above the earth or at 100 km, passengers on either vehicle will experience the same degree of weightlessness.

Continue reading “Space Sunday: tourist flights, landers, moons and rovers”

Space Sunday: the little rover that could

MER Opportunity: the modest rover that cast a huge shadow to fit its larger-than-life perseverance. Credit: NASA/JPL / MSSS

It is therefore that I am standing here with a sense of deep appreciation and gratitude, that I declare the Opportunity mission as complete. For more than a decade, Opportunity has been an icon in the field of planetary exploration, teaching us about Mars’ ancient past as a wet, potentially habitable planet, and revealing uncharted Martian landscapes.

– Thomas Zurbuchen, Associate Administrator for NASA’s Science Mission Directorate

These words, spoken on February 13th, 2019, marked the official end of the longest running rover mission thus far to another planet.

Designed to last just 90 Martian days and travel 1,000 metres (1,100 yards), the Mars Exploration Rover (REM) Opportunity vastly surpassed all expectations in its endurance, scientific value and longevity. In addition to exceeding its life expectancy by 60 times, it travelled more than 45 km (28 mi) by the time it reached its most appropriate final resting spot on Mars – Perseverance Valley.

Across a decade and half, Opportunity – or “Oppy” to its fans – captivated people’s imaginations around the globe, and while it  became somewhat overshadowed by its much bigger cousin, Curiosity, from 2012 onwards, “Oppy” nevertheless broke the ground for the surface exploration of Mars, together (for a time, at least), with its sibling rover, Spirit.

The MER rovers, Spirit and Opportunity and their instruments

From the outset, the MER programme was a daring one: to place two vehicles on the surface of Mars, capable of self-driving across the surface and carrying out a range of scientific tasks. At the time it was conceived, Mars was known to be a notoriously difficult target to reach: for some reason over one-third of the missions intended to reach the Red Planet failed. Some were lost shortly after launch; others failed whilst en route; other experienced upset or failure on arrival. Indeed this Hence why the MER project had two rovers: if one fell afoul of the Great Galactic Ghoul, the other would survive.

To pave the way for the rovers, NASA undertook the Pathfinder mission in the late 1990s. This comprised a Mars lander complete with a very small-scale (just 65 cm / 2.2ft in length) rover called Sojourner. While both the lander and the rover carried science instruments and carried out worthwhile science, a major element of the mission was to test the entry, descent and landing system the MER mission would use: a completely loopy sounding mix of parachutes and a cocoon of air bags designed to rapidly inflate around a payload just before it reached the surface of Mars and protect it and it bounced its way to a resting position before deflating, the payload automatically righting itself in the process.

The Pathfinder airbag system, very similar to the system used by the MER programme, on test at NASA’s Jet Propulsion Laboratory, June 1995. Credit: NASA/JPL

In many respects, the Pathfinder mission (the lander from which are later renamed the Carl Sagan Memorial Station, in honour of the great planetary scientist, humanitarian, global thinker and Mars exploration advocate, Carl Sagan) was the MER’s mission lucky charm.

Not only did the mission prove the landing system, necessary because “conventional” retro-rocket landing systems would have massively increased the complexity and cost of sending large rovers to Mars, both lander and rover operated far beyond their anticipated life spans: the lander for 9 months (compared to an anticipated 85 days) and the rover for 85 days (rather than the anticipated 7 days. Incidentally, it Sojourner was the first Mars mission to employ a form of VR: the “driver” on Earth would wear a set of 3D goggles that visualised the rover’s surroundings digitally, so a path to be mapped using a special “driving” system. The driving commands would be saved and later transmitted to Mars as a batch of commands the rover would then execute).

April 15th, 2003: Opportunity, with solar panel already folded and drive system collapsed, is prepared for enclosure within the petals of its landing system. Credit: NASA/JPL

The MER rovers were launched in June (Spirit) and July (Opportunity) of 2003, and arrived on Mars on January 4th and January 25th, 2004, respectively, just after Europe’s Mars Express mission had arrived in Martian orbit at Christmas, 2003. The landings were fraught with concerns: the UK’s Beagle 2 lander, delivered to Mars by Mars Express, had arrived on the planet on Christmas Day 2003, but all attempts to communicate with it had failed.

Obviously, the EDL systems for both landers worked perfectly. Spirit landed in Gusev crater, originally thought to be a dry lake bed. However, the rover’s findings disproved this, revealing the crater to be largely filled with natural debris. In all, Spirit operated on a mobile basis for almost 5 years and 4 months before it became bogged down in a “sand trap” on May 1st, 2009. When attempts to free it failed, the rover became a static station until it stopped communicating in March 2010. NASA then spent 14 months attempting to re-established contact before declaring Spirit’s, mission was at an end on May 24th, 2011.

Continue reading “Space Sunday: the little rover that could”

Space Sunday: Mars, Uranus and Neptune

The ExoMars Rover Rosalind Franklin, 2018. Cedit: EADS Astrium UK

It’s been a mission almost 20 years in the making, but it finally has a vehicle name: the European Space Agency’s (ESA) ExoMars rover is now officially called Rosalind Franklin.

In 2001, ESA announced the goal of landing a large rover vehicle on Mars in 2009 as a part of its Aurora programme for the human exploration of the Red Planet. As an optional programme, Aurora allowed ESA member states to determine which elements they would like to support. In 2005, the UK’s EADS Astrium indicated it would undertake the design and construction of the rover, then referred to as ExoMars.

Over the next decade plus, ExoMars as a whole underwent numerous changes in scope and capability. Some of these changes were driven from within ESA. For example, in order to meet initial launch requirements using a Russian rocket, the rover was scaled down to just 180 kg. However, this left it was just 6 kg for the science payload, prompting a move to using a more powerful Ariane launcher, allowing for a larger rover and science payload – but at twice the price of a Russian launch.

Other changes came about through external influences. In 2009, ESA signed an agreement with America’s NASA, which would have seen the a joint ESA / NASA mission, with the US agency taking responsibility for the rover (renamed the Mars Astrobiology Explorer-Cacher, or MAX-C) and ESA producing the lander and an orbiter – the Trace Gas Orbiter. Less than a year later, MAX-C was scrapped in favour (once again) of a large 600 kg European rover.

The ExoMars rover over the years. Top left: 2007 (credit: Jastrow). Bottom left: 2009 (credit: Mike Peel) and 2015 (credit: Cmglee)

Then in 2011 NASA withdrew from the agreement, forcing a further reassessment of the rover and the ExoMars project overall. In 2013, ESA and Russia’s Roscosmos signed an agreement that would see a revised ExoMars mission  – the rover and the Trace Gas Orbiter (TGO) – flown atop two uprated Proton rockets in 2016 and 2018, with the first launch featuring the TGO, which arrived in Mars orbit in October 2016. The second would be the rover mission, intended for launch in 2018.

The switch back to using a Russian launch vehicle meant the rover had to go through a further redesign in order to shed 290 kg of mass. By 2016, all of this left the ExoMars project breaking through its budget cap of €1 billion. In order to secure the required €1000 million needed to complete the project’s development and launch costs, the launch would have to be pushed back until 2020. It is currently slated for lift-off on July 25th, 2020 and arrive on Mars on March 19th, 2021.

Rosalind Franklin. Credit: Jewish Chronicle Archive / Heritage-Images

The rover’s name has been given in honour of Rosalind Elsie Franklin (July 25th, 1920 – April 16th, 1958), an English chemist and X-ray crystallographer who made contributions to the understanding of the molecular structures of DNA (deoxyribonucleic acid), RNA (ribonucleic acid), viruses, coal, and graphite. Although her works on coal and viruses were appreciated in her lifetime, her contributions to the discovery of the structure of DNA were largely recognised posthumously.

Her name was one of 36,000 submissions by citizens from all ESA Member States, following a competition launched by the UK Space Agency in July 2018. It was selected by a panel of experts before being officially announced by UK astronaut Tim Peake on Thursday, February 7th, 2019 at an event in Stevenage UK, where the rover has been built.

Rosalind Franklin is one of science’s most influential women, and her part in the discovery of the structure of DNA was truly ground-breaking. It’s fitting that the robot bearing her name will search for the building blocks of life on Mars, as she did so on Earth through her work on DNA.

– Alice Bunn, international director of the U.K. Space Agency

In a slight tweak on the usual convention – most spacecraft named in honour of a person are referred to by the individual’s last name – the rover is already being referred to simply as “Rosalind” (although in fairness, its prototypes and test units have also been known by first names, such as “Bruno”).

Once on Mars, the rover will be the first of its kind to combine the capability to roam around Mars and to study it at depth. To do this, it is equipped with a drill capable of reaching down two metres (6ft 6in) below the surface, gather samples for analysis using a set of instruments collective called the Pasteur Suite, searching for evidence of past – and perhaps even present – life buried underground, where water is known to be present and where harsh solar radiation cannot penetrate. In addition, the rover has a suite of instruments to study the atmosphere, examine the sub-surface environment with radar to locate areas to drill for samples, identify deposits of water ice, etc. Further, ESA is currently considering including a small “scout” rover, designed to identify areas of soft sand, etc., where Rosalind might get stuck trying to traverse.

Rosalind will be delivered to the surface of Mars by a 1.8 tonne landing platform built by Roscosmos. This will use a combination of parachutes and retro-rockets to achieve a soft landing. The current primary landing site for the rover is Oxia Planum, a large plain in the northern hemisphere of Mars, which contains one of the largest exposures of clay-bearing rocks on the planet which are roughly 3.9 billion years old. These are rich in iron-magnesium, indicating water played a role in their formation. The area comprises numerous valley systems with the exposed rocks exhibiting different compositions, indicating a variety of deposition and wetting environments, making it an ideal subject for exploration.

Hubble Reveals Dynamic Atmospheres of Uranus and Neptune

As well as studying deep space, the Hubble Space Telescope routinely keeps its eye on the planets of the solar system. In doing so, it has uncovered a new mysterious dark storm on Neptune and provided a fresh look at a long-lived storm circling around the north polar region on Uranus.

 A Hubble image of Neptune taken in September 2018 showing the latest storm vortex in the northern hemisphere. Credit: NASA, ESA, and M.H. Wong and A. Hsu (University of California, Berkeley)

The latest images of Neptune from Hubble show a large, dark storm in the planet’s northern hemisphere. It is fourth and latest mysterious dark vortex captured by Hubble since 1993. Prior to this, two other storms were spotted by Voyager 2 in 1989 as it flew by the remote planet. A study led by University of California, Berkeley, undergraduate student Andrew Hsu estimates that the storms appear every four to six years at different latitudes and disappear after about two years.

The current storm was spotted by Hubble in September 2018, and is estimated to be 10,880 km (6,800 mi) across. It is accompanied by white companion “clouds”, similar to those seen with previous vortices. Similar to the pancake-shaped clouds that appear when air is pushed up over mountains on Earth, these while formations are thought to be the result of the vortices perturbing the lower reaches of the atmosphere and diverting it upward, causing gases to freeze into methane ice crystals. The long, thin cloud to the left of the dark spot is a transient feature that is not part of the storm system.

Continue reading “Space Sunday: Mars, Uranus and Neptune”