Category: Space Sunday

On Saturday, May 30th, 2020 the United States successfully launched astronauts into orbit from American soil for the first time since July 8th, 2011. It came after an initial attempt on May 27th, 2020 had to be scrubbed (called off) due to adverse weather conditions putting the launch vehicle at risk of a possible electrical strike.

As I noted in my previous Space Sunday piece, the primary goal of the mission is to confirm the SpaceX Crew Dragon vehicle is ready to commence operations ferrying crew to and from the International Space Station. Intended to fly up to four crew at a time on such missions, for this final test flight, Crew Dragon lifted-off with only two crew aboard: NASA veterans Robert L. Behnken (flight pilot) and Douglas G. Hurley (commander).

Weather was also a concern in the run-up to the May 30th launch, with NASA putting a chance of lift-off at 50/50 through to less than an hour ahead of the launch time. However, after a burst of rain in the area of Kennedy Space Centre as the Falcon 9 launch vehicle was being prepared for lift-off, the weather situation both around the Florida Cape and downrange of the launch site and along the track of the vehicle’s line of ascent, cleared sufficiently for the launch to go ahead.

The entire launch, from the astronauts suit-up in the crew room at Kennedy Space Centre, through lift-off, ascent to orbit, on-orbit operations and the rendezvous and docking with the International Space Station some 19 hours after launch, was covered entirely live through NASA TV and SpaceX on You Tube and other channels. This coverage made it one of the mos-watched launches of a space vehicle despite the limitations of travel in place due to the SARS-CoV-2 pandemic, with 1.5 million people watching the SpaceX relay of the NASA feed alone.

Following their arrival at the launch pad some 2+ hours ahead of the the launch, the astronauts – known as “the Dads” to the SpaceX team – travelled to the top of the launch tower prior to ingressing into the Crew Dragon vehicle and performing a series of pre-flight checks both before and after the crew hatch was closed-out by the fight support crew.

At around an hour prior to launch and with the flight support crew clear of the tower, the access arm was rotated clear and fuelling of the Falcon 9’s first and second stage tanks commenced as the weather clearance was given. Unlike Apollo and the shuttle, the SpaceX vehicles go through fuelling as a last stage of ground operations to minimise the amount of fuel venting / topping-up that is required as the super-cold liquid propellants start to slowly warm despite insulation and cooling.

A crucial aspect of the Demo-2 launch was that orbital mechanics demanded the vehicle had to lift-off precisely on time – there could be no “holds” that delayed it beyond the appointed lift-off time. Were launch to be delayed, even by a few minutes, the Crew Dragon would reach orbit at the wrong point related to the ISS, and so and rendezvous would be much harder, if not impossible, given what needed to be achieved in the flight ahead of reaching the space station.

So, at 19:22:45 UTC, precisely on schedule, the nine motors of the Falcon 9’s first stage igniting, lifting the black-and-white rocket and capsule vehicle smoothly off the pad. This marked a further first for the mission: not only was it the first US crewed mission into space undertaken from US soil bult and operated by a private company, the entire launch process was run by SpaceX and not by NASA’s Mission Operations Control Room (MOCR – or “moe-kerr”) at the Johnson Space Centre (JSC), although the latter were obviously looking over SpaceX’s shoulder and monitoring things, with the ISS Fly Operations Centre fully “in the loop”.

Ascent to orbit lasted some 8 minutes – although to all those watching, it probably seemed a lot quicker. Powering the vehicle through the denser part of the atmosphere, the Falcon’s first stage reached MECO (main engine cut-off) just over 2 minutes after launch. Separating, this continued along a ballistic trajectory, flicking itself around to deploy vanes to help with its descent back though the atmosphere so it might make a landing on the autonomous drone ship Of Course I Still Love You.

Camera footage from the first stage, transmitted as the Falcon’s second stage continued to boost the Crew Dragon vehicle to orbit, showed it orienting itself using its attitude thrusters, prior to three of the Raptor engines firing to slow it down and cushion it as it dropped back into denser atmosphere. From here, it dropped smoothly back towards the drone ship, the deployed vanes holding it upright. Unfortunately, video footage was lost prior to touch-down, but moments later, the feed resumed, showing the stage sitting on the ship’s deck as high above, the Falcon’s second stage reached SECO – Second (Stage) Engine Cut-off, and shortly after, the Dragon separated from it.

Continue reading “Space Sunday: how to fly your Dragon” →

If all goes according to plan, the United States will make its first crewed launch from its home soil since the space shuttle programme drew to a close in 2011.

On May 27th, 2020, shrouded in additional safety protocols to protect crews from the SARS-CoV-2 virus, a SpaceX Falcon 9 booster should lift off from the company’s launched pad – leased from NASA – at Launch Complex 39A, Kennedy Space Centre, Florida. Aboard the Crew Dragon vehicle at the top of the rocket will be NASA veterans Robert L. Behnken and Douglas G. Hurley, who will be heading to the International Space Station (ISS).

The primary goal of the mission – referred to as Dmeo-2 by SpaceX and SpX DM-2by NASA – is to confirm the SpaceX Crew Dragon vehicle is ready to commence operations ferrying crew to and from the ISS. To this end, NASA has contracted SpaceX to provide the agency with 6 Crew Dragon launches to carry four astronauts at a time to and from the ISS; the vehicle is actually capable of carrying up to seven per flight, but NASA will use the additional capacity for light cargo and equipment bound for the ISS.

In addition to flying crews on behalf of NASA, SpaceX has also been contracted by Axiom Space to fly one Axiom professional astronaut and three private astronauts at a time to the ISS for periods of around 10 days at a cost of US $55 a seat. However, these private astronauts are not necessarily space tourists: Axiom is committed to developing the world’s first fully commercial space station.

As a part of this, the company entered into an agreement with NASA to dock three of its own space station modules to the ISS to kick-start their station development, with the first module potentially being launched in 2024. These modules will be used to host experiments and research by Axiom and their partners; following the retirement of the ISS (around 2028), Axiom plan to launch their own power and thermal module, airlock system and habitation module to replace the ISS facilities.

Not that SpaceX and the Crew Dragon won’t be involved in space tourism; the company has also partnered with Space Adventures to provide sets to fly up to four space tourists at is time on orbital flights lasting between three and five days. These will have an apogee three times that of the ISS and higher than the Earth orbital altitude record set by Gemini 11 in 1966.

In the meantime , this first crewed flight with see Behnken  and Hurley rendezvous with the ISS the day after launch (May 28th if the launch goes ahead as planned). The docking will be carried our autonomously – as will the majority of the flight, although the crew can fly the vehicle manually at any time, including the docking. Once at the ISS, the crew and vehicle will remain there for around four weeks, before making a return to Earth.

Hurley and Behnken arrived at Kennedy Space Centre on May 20th, ahead of the final flight readiness review (FRR) for the mission, which took place on May 22nd. This cleared the mission for its planned launch after an extensive review of all the Crew Dragon’s systems, notably its parachute system, which has been a point of concern for NASA after the parachutes had to go through a complete redesign and a rapid series of tests in the lead-up the the flight.

Following the FRR, SpaceX proceeded with a standard static-fire test of the Falcon 9’s first stage engines in readiness for launch, which the booster completed successfully. On Saturday, May 23rd, crew and vehicle went through full launch dress rehearsal. This will be followed by a final series of tests and checks on both the booster and Crew Dragon vehicle in the lead up to the launch, which is currently scheduled for 16:33 EDT on May 27th. It will come just over a year since Crew Dragon made its first (uncrewed) flight to the ISS in May 2019.

Crew Dragon is intended to be semi-reusable, with each capsule potentially capable of being re-flown after refurbishment following a flight. However, the vehicles used by NASA will only be flown once each. It has been said this is due in part to a decision not to use Dragon’s propulsive landing capabilities with NASA missions, but to instead make ocean splashdowns when returning crews to Earth, exposing the capsules to sea water contamination. Even so, it is estimated the per-seat cost for launching NASA astronauts on Crew Dragon is around 40% less than the cost of a seat on the Boeing Starliner.

Continue reading “Space Sunday: launches, names, and departures” →

Of all the planets and moons in the solar system, the two that – next to Earth – are likely to be homes to oceans of liquid water are Jupiter’s moon Europa, and Saturn’s Moon Enceladus. The latter, as I’ve noted in this column, has visible evidence of geysers venting water vapour around its southern polar regions, while in November 2019, the the W.M. Keck Observatory indicated they had directly detected water vapour around Europa (see here for more) – evidence that has since been added to through further study of the data gathered by NASA’s Galileo mission that ended in 2003.

Given their distance from the Sun, both of these moons are covered in shell of icy material  that is believed to encase a liquid water ocean, likely heated from within by hydrothermal vents, themselves the result of both moons being “flexed” by the gravitational influence of their parent planets and the other large moons orbiting them. And where there is water, heat and a source of energy for sustenance, there is a possibility that life may also be present – which makes both Enceladus and Europa potential destinations in the search for life beyond our own world; and of the two, Europa is somewhat “easier” to reach.

To this end, and again as has been written about in this column, in 2024 NASA intends to send the Europa Clipper to the Jovian system, placing it in a orbit around Jupiter that will allow it to make repeated fly-bys of Europa, joining the European Space Agency’s Jupiter Icy Moons Explorer allowing it so study the moon in detail, and characterise its surface and any ocean that might lay beneath.

However, to have a real chance of detecting any evidence of microbial life on Europa, scientists argue that a landing there is required, and as planetary scientist Conor A Nixon reminded me via Tweeter, a proposal to put a lander on the surface of Europa has been in development for over two years – although it has yet to reach the point of actually being funded. Were it to go ahead, it would – amongst other things – be the heaviest robot mission launched from Earth; so heavy, it would require either the Falcon Heavy or NASA’s massive Space Launch System (SLS) to throw it on its way to Jupiter – with the SLS being the preferred vehicle, as it would allow the mission to reach Jupiter after just a single gravity assist from Earth, shortening the flight time.

The primary objectives of the mission would be to search for subsurface biosignatures; to characterise the surface and subsurface properties at the scale of the lander to support future exploration of Europa and determine the proximity of liquid water and recently erupted material near the lander’s location; and assess the habitability of Europa via in situ techniques uniquely available to a landed mission. Under current plans, last revised in 2019, the mission  – outside of this launcher – will comprise five core elements:

• The Europa Lander: a battery-powered vehicle intended to operate on the surface of Europa for 22 terrestrial days, and carrying a suite of around 14 scientific instruments / experiments.
• The Descent Stage (DS): to reduce the risk of contaminating / damaging the lander’s touch-down point, it will be winched down to the surface by a “sky crane” vehicle similar to the one used to put the Curiosity lander on Mars and will be used with the Perseverance rover in February 2021. Once the sky crane has done its job, the sky crane will boost itself into an orbit where it will eventually burn-up in Jupiter’s upper atmosphere.
  • Together, the lander and the DS form what NASA call the Powered Descent Vehicle (PDV).
• The De-Orbit Stage (DOS): a propulsion unit intended to slow the PDV into a decent to the surface of Europa.
  • When combined the DOS and PDV form the De-Orbit Vehicle (DOV).
• This assembly is carried to Jupiter within the carrier stage, comprising two parts:
  • The carrier vehicle, which provides communications, power and flight management hardware and software.
  • A protective bio-barrier dome designed to protect PDV from the risk of contamination / damage during the 5-year trip to Jupiter.

Continue reading “Space Sunday: to land on Europa” →

China has successfully completed an uncrewed test-flight of its next generation of space vehicles that will support future crewed operations in Earth orbit and be a part of missions to the Moon – and possibly beyond.

The new craft – which resembles the Apollo command and service module (CSM) combination used by NASA in the 1960s and early 1970s (or, if you prefer, Boeing’s current CST-100 Starliner capsule and service module) – was launched atop a Long March 5B rocket, China’s most powerful launch vehicle, on Tuesday May 5th. From the launch pad at the Wenchang launch site on the southern island of Hainan, the vehicle took 8 minutes to rise to its initial orbital separation altitude, where it successfully entered orbit. A second payload – that of a cargo return capsule also undergoing tests – also successfully separated from the booster.

While the crew capsule test vehicle would remain in space for several days, allowing it to complete a series of automated tests, the cargo capsule – designed to return equipment and experiments from China’s upcoming space station – had been due to return to Earth on Wednesday, May 6th. Unlike the crewed vehicle, the cargo unit is designed to use an “inflatable” heat shield during re-entry.

Called a “ballute” (a portmanteau of balloon and parachute), this approach to inflatable systems was initially developed in the last 1950s as a parachute-like braking device optimised for use at high altitudes and supersonic velocities. In the 1960’s, ballutes were included as part of the astronaut escape system in NASA’s Gemini missions. More recently, a number of organisations and countries have been looking at there use as re-entry systems as they are lighter and potentially less complex than conventional re-entry systems.

In this instance, it appears the ballute may have failed. Following re-entry, the China National Space Agency (CNSA) announced the cargo vehicle has suffered an “anomaly” that was being investigated – with no further information forthcoming.

The crew capsule, however, completed its mission entirely successfully, performing a number of orbital manoeuvres, testing the deployment of the vital solar panels and carrying out a series of communications tests.

The extended orbit of the vehicle carried it some 8,000 km altitude – greater than that of the Orion uncrewed flight test in 2018. This meant it would be able to make an atmospheric entry at speeds matching a return from the Moon – putting the heat shield to its ultimate test.

Ths initial de-orbit burn took place on Friday, May 8th, at 5:21 UTC, after which the capsule separated from its service module. Following a successful atmospheric entry, the vehicle deployed three main parachutes to make the descent over the planned Dongfeng desert landing area. Shortly before landing, self-inflating airbags were deployed to soften the impact, which occurred at 5:49 UTC. In all, the vehicle spent more than 2 days and 19 hours in orbit.

When crewed flight commence, the vehicle will be capable of carrying a combination of crew and cargo, with a minimum of 3 crew (and up to 500 kg of cargo, if required) required for a launch and operation of the vehicle, with a maximum of 6 (or 7 according to some Chinese sources) crew. The core of the capsule is designed to be used over a maximum of ten flights, with the heat shield being completely replaced after each flight, with the side thermal protection system also being refurbished.

The success of the flight, together with that of the Long March 5B – making its first launch – has been reported as now opening the door to a slate of 11 missions revolving around space station construction, with CNSA indicating they plan to complete space station construction by the end of 2022.

However, one side-effect of this flight is that the 20-tonne core stage of rocket also reached orbital velocity. It is expected to make an uncontrolled re-entry into the atmosphere on Monday, May 11th, the largest man-man object to date to do so. Any elements surviving re-entry should splash down in the Indian ocean.

Continue reading “Space Sunday: rockets, landers, FRBs and the Moon” →

China is readying for the next phases of its space ambitions.

In July, the country is due to launch its first mission to Mars. Officially referred to as the Mars Global Remote Sensing Orbiter and Small Rover mission, it comprises an orbiter, a lander vehicle and a small rover, with the orbiter and rover between them carrying the majority of the mission’s 18 scientific instruments.

The priorities for the mission include finding evidence of current or previous microbial life, and evaluating the planet’s surface and environment. In addition, solo and joint explorations of Mars, the orbiter and rover will produce maps of the Martian surface topography, and obtain data on soil characteristics, material composition, water ice, atmospheric composition, ionosphere field intensity, and other scientific data.

On April 24th, the Chinese announced the lander vehicle is to be called Tianwen, or “Quest for Heavenly Truth.” It will use a landing system comprising a parachute, retrorockets, and an airbag to achieve a soft landing. The rover will be solar powered, as with China’s Yutu family of lunar rovers.

The name represents the Chinese people’s relentless pursuit of truth, the country’s cultural inheritance of its understanding of nature and universe, as well as the unending explorations in science and technology.

– China’s National Space Administration (CNSA) statement

The Chinese tend to be fairly close-lipped about their space missions (among many other things), but from what has been announced, the mission is being built along similar lines to both NASA surface missions like InSight and MSL, and Europe’s ExoMars orbiter / lander missions. Following its arrival in Mars orbit in February 2021, the combined orbiter / lander will remain there for an unspecified period while the intended landing site is confirmed.

Once on the surface, the 200 gram 6-wheeled rover is expected to operate for at least 3 months, with a selection of its science systems comprising Ground-Penetrating Radar (GPR), to image about 100 m below the Martian surface, a magnetic field detector, a Mars meteorological instrument and multiple camera instruments. The rover is expected to be given its own name in due course.

At the same time, China rolled out a Long March 5B launcher in preparation for a mission to prove space station launch capabilities and to test a new spacecraft for deep space human space flight. It is expected to lift-off on, or around, May 5th 2020, carrying the first of China’s new generation of crew-capable vehicles designed to supersede the Soyuz-derived Shenzhou craft.

The new craft resembles an Apollo command and service module (CSM) combination, comprising a conical capsule vehicle protected by an atmospheric entry heat shield, and a cylindrical service module that provides the primary source of power and propulsion when operating in space. For the first flight, it will carry around 10 tonnes of fuel, intended to allow the vehicle to offer a similar mass to the core stage of the upcoming Chinese space station. The fuel will also allow the vehicle to reach a high orbit and and achieve a fast re-entry velocity.

This latter is important as the the new vehicle is intended for deep space crewed missions, including acting as the carrier for crews engaged in future missions to the Moon. Such missions will – like America’s Orion coming back from the Moon – return to Earth as a higher velocity than an orbital craft. As such, the first flight of this new Chinese vehicle will be somewhat similar in nature to the Orion’s first uncrewed flight in 2018.

To achieve its full envelope of uses, the new crew vehicle comes in two variants: a capsule and small service module which together weigh 14 tonnes, to be used in local orbital flights, and a version with a larger service module, giving a mass of 20 tonnes for the combined craft. This will likely be used for missions into deeper space. Either craft be able to carry up to six astronauts, or three astronauts and 500 kg of cargo to low Earth orbit.

Overall, the May launch of the vehicle has a lot hinging on it. A successful flight will clear the way for the two-month-long launch campaign required for the Mars Global Remote Sensing Orbiter and Small Rover mission mentioned above, using a Long March 5. In will also be see as opening the way for the Long March 5B vehicle to undergo a series of launches ahead of placing the 20-tonne Tianhe module, intended to be the core element of China’s new space station, due in early 2021. Weighing 20 tonnes, the module’s launch will mark the first in about a dozen that will be needed to complete the station between 2021 and 2022 /23.

When is an Exoplanet Not and Exoplanet?

As I’ve frequently remarked in these pages, we’ve so far confirmed the presence of over 4,000 exoplanets orbiting other stars. The number is such that it’s easy to think that detecting these worlds is just a matter of observing and waiting for that regular tell-tale dipping of brightness in a starts luminosity as seen from our orbiting telescopes, and which has been the more common means of detecting the worlds around other stars.

However, finding and confirming the presence of exoplanets is a complicated process, one that can be ripe with false positives. An example of this is Fomalhaut b, which has been puzzling astronomers since it was first observed in 2004. Orbiting the A-type main-sequence star Fomalhaut, some 25 light-years from Earth in the constellation of Piscis Austrinus, the planet was first observed by the Hubble Space Telescope, marking as the first to be detected in visible wavelengths (that is. the Direct Imaging Method).

Continue reading “Space Sunday: China’s missions and a disappearing “planet”” →