Space Sunday: Mars, starships, rockets and spaceplanes

A panorama of Jezero crater captured by the Mastcam-Z system on Perseverance showing the stern deck of the rover with the crater rim on the far horizon. It comprises 142 individual images taken on Sol 3, the third Martian day of the mission (Feb. 21st, 2021). Credit: NASA/JPL / ASU / MSSS

NASA’s latest rover arrived on Mars on February 18th, 2021 as the core part of the agency’s Mars 2020 mission, the rover Perseverance, arrived on the red planet (see:  Space Sunday: ‘Perseverance will get you anywhere’ and  Space update: 2020 landing video and audio of the Martian wind).  Since then, work has been continuing in commissioning the rover ready to start its science operations, and it has continued to return images of its new home in Jezero Crater. And as has now been widely reported, it gave Internet sleuths a coded message to decode.

This came in the form of the red and white markings on the mission’s supersonic parachute. Intended to provide data on how the parachute unfurled and performed, it also contained a message in binary code – something hinted at by Allen Chen, the Entry, Descent and Landing lead for the mission whist referencing the parachute’s performance during the February 22nd press briefing I reported on in the second of the two articles noted above.

In addition to enabling incredible science, we hope our efforts in our engineering can inspire others.  Sometimes we leave messages in our work for others to find for that purpose, so we invite you all to give it a shot and show your work.

– Allen Chen, the Mars 2020 EDL lead, February 22nd

With the parachute lines edited out, a graphic overlaid onto the Mars 2020 parachute reveals the hidden message (read counter-clockwise from the centre outwards). Credit: NASA

The message, in binary code, was cracked in six hours, proving to the saying Dare Mighty Things, a phrase attributed to Theodore Roosevelt, the 26th President of the United States and the adopted motto of the Jet Propulsion Laboratory, responsible for the mission, together with the latitude and longitude of JPL’s offices in Pasadena, California.

Nor is the only coded message the rover carries. While its wheels are of  an improved design over those used on the Curiosity rover – which celebrated 3,000 days of continuous operations on Mars on January 12th, 2021 – the wheels on Perseverance also carry the letters “JPL” cut into their treads in Morse code.

Other curios carried by the rover include a “family portrait” of NASA rover types that run from tiny Sojourner, which arrived on Mars in 1998 as a part of the Mars Pathfinder mission, through the twins of Spirit and Opportunity Mars Exploration Rover mission, to Curiosity and Perseverance. Like a plaque to healthcare workers around the globe, this is something of a decorative / commemorative piece.

Captured by the NavCam system, the “family portrait”. of NASA rovers from Sojourner to Perseverance. Credit: NASA/JPL / MSSS

Another of the commemorative piece son the rover is a panel on which are mounted the three microchips that contain the names of the 10,932,295 people who applied to have their name included in the mission (you can also apply to have your name included in future missions), which located on the rover’s aft cross-beam, above its nuclear power supply.

Some of the curios also fulfil a practical use. For example, the SHERLOC ultraviolet Raman spectrometer mounted on the rover’s robot arm includes five samples of materials that may be used in future spacesuits that may be used on Mars.

A cropped view of the panorama seen at the top of this article showing the location of the name-carrying microchips on Perseverance (l). On the right, the microchips shortly after being maounted on the rover’s aft cross-beam. Credit: NASA/JPL

The intent of these samples is to test how the materials in them react to the Martian environment; however one of them – made of the materials used in helmet visors contains behind it a geocache inscribed with the address of the instrument’s fictional name-sake (221B Baker Street).

Mounted on the deck of the rover is a camera calibration target. Located between the colour and reflective marks on the outer ring of the calibration target are a series of symbols representing life on Earth which is intended to reflect the mission’s primary goal of looking for evidence of past life on Mars, whilst the Mastcam-Z system on the rover includes the massage:

Are we alone? We came here to look for signs of life, and to collect samples of Mars for study on Earth. To those who follow, we wish a safe journey and the joy of discovery.

– from the Perseverance rover

The sample panel on the SHERLOC instrument includes 5 samples of spacesuit materials including, left, visor material with a geocache behind it bearing the legendary address of Sherlock Holmes. Credit: NASA/JPL

Since its arrival at Jezero Crater, Perseverance has returned thousands of images of its surroundings,   commissioning and testing continues. It’ll still be another couple of weeks or so before the surface mission properly commences. These have revealed that in coming down roughly 2km from the mid-point of its landing area – a remarkable achievement in itself -the rover has found itself in a rich geological playground, including features formed by both the passage of water and wind.

Some, such as “Seal Harbour Rock” – most likely formed by the passage of wind – already has geologist excited.

Are these volcanic rocks? Are these carbonate rocks? Are these something else? Do they have coatings on them? We don’t know  – yet. We don’t have any chemical data or mineral data on them; but, boy, they’re certainly interesting, and part of the story about what’s going on here is going to be told when we get more detailed information on these rocks and some of the other materials in this area.

– Jim Bell, School of Earth and Space Exploration, Arizona State University

A broader version of the panorama over the back of the perseverance rover, with the position of “Seal Harbour Rock”, likely the result of wind erosion, marked and the rock itself highlighted in the inset image. Credit: NASA/JPL

China Starts Preparations for Rover Landing

Having arrived in Mars orbit the week before Mars 2020 made its Martian debut, China’s Tianwen-1 mission as entered a temporary parking orbit around Mars in anticipation of landing a rover on the planet’s surface in the coming months.

Comprising an orbiter vehicle, a lander and the rover, Tianwen-1 is China’s first interplanetary mission, Tianwen-1 will remain in its new circular orbit for around 3 months. During this time the orbiter, alongside of its main science programme, will collect high-resolution images of the surface of Mars, notably of the proposed landing site for the lander/rover combination.

Released in October 2020, this image captured from a camera mounted off the end of the orbiter’s solar panels shows the gold-colour orbiter an the land / rover contained within their protective aeroshell. Credit: China National Space Administration

The landing itself will follow a similar profile to those of NASA’s Pathfinder and MER missions: after entry into the atmosphere, the lander/rover will be slowed by parachute, with the final part of the decent using rocket motors to reduce speed before airbags are inflated to protect the vehicles through landing.

If successful, the lander will deploy the solar-powered rover, which will collect data on underground water and look for evidence that the planet may have once harboured microscopic life.

SpaceX Readies Starship for Next Flight Test

SpaceX is in the process of carrying out final tests and checks of its Starship SN10 prototype ahead of its anticipated launch, which could take place in the first week of March.

On February 20th, the Federal Aviation Authority (FAA) concluded its investigation into the loss of the SN9 prototype, stating  that the vehicle failed within the bounds of safety requirements around the company’s Boca Chica, Texas development and test centre and posed no threat to life or property. Following this, on Monday, February 22nd, the FAA granted SpaceX a modification to its launch licence, allowing the company to attempt a static fire test of the vehicle’s motors. Unfortunately, what appears to have been a fault within the fuel loading systems led to the attempt being scrubbed.

Starship SN10 on its launch stand with the tank farm for fuelling operations in front of it. Credit: Mary/BocaChicaGal / NASASpaceflight.com

A  second attempt on Tuesday, February 23rd saw all three engines successfully ignite for around 2 seconds. However, analysis of data post-test resulted in one of the motors being swapped-out for a new unit. A further static test then took place on Friday 26th, which was also apparently successful, prompting the speculation that SN10 could fly in the first week of March.

This will be similar to that of SN9 – a climb to around 10km altitude, followed by a “flip-over” manoeuvre to allow the vehicle to “skydive” horizontally towards the ground. During the final phase of this drop, the vehicle will re-light all three of it Raptor motors and attempt to flip itself upright once more to make a tail-first landing.

It is hoped that the initial re-ignition of all three engines will avoid issues seen with both the SN8 and SN9 flights. With those, only two of the Raptor engines were re-lit for the flip-up manoeuvre – resulting in insufficient thrust to either slow the vehicle’s rate of descent for landing (SN8) or complete the flip-up (SN9) when each vehicle suffered a failure with one of the two motors (albeit for different reasons).

SpaceX has indicated that assuming all three motors lit as expected, the one that provides the last amount of thrust during the flip-up will be immediately shut-down, allowing the vehicle to make a (hopefully) successful landing on the remaining two engines.

The current status of SpaceX Starship and Super Heavy booster prototypes at Boca Chica. Credit: Brendan Lewis

Should SN10 also be lost, SN11 has reached a point where it is ready for transfer to a launch stand in readiness for its test flight. After that vehicle will come SN15 (vehicles SN12-SN14 having been discontinued). This is the first of a more advanced vehicle build, potentially allowing for higher altitude testing, with SN16-SN19 set to follow it.

Amidst all this work, footage captured through the open doors of one of the facility’s fabrication tents  gave a tantalising glimpse of  what appears to be a major section of another (unspecified) SN vehicle with one side of it coated in heat protection material, against which thermal protection tiles were also  being affixed. This prompted comments that SpaceX is looking towards some extremely high altitude flights to allow testing of the thermal materials vital to Starship’s protection during re-entry into the Earth’s denser atmosphere, although SpaceX has yet to comment on this.

An unidentified section of Starship hull covered on one side with what appears to be a white, intumescent carbon-fibre blanketing, over which thermal protection tiles (arrowed) are being mounted. Credit Mary/BocaChicaGal / NASASpaceflight.com

Amidst all the latest work the company is engaged in, which included continued commercial payload launches for customers, on-going launches of its Starlink satellite broadband service and activities in support for NASA and the ISS, SpaceX also confirmed it had raised  a further US $850 million from 69 investors in its latest round of investment, valuing the company at US $74 billion.

Delays to Tests and Flights

Delays have been announced to the testing and initial flights of a number of space and sub-orbital systems

On February 22nd, NASA announced the follow-up Hot Fire Test of the four RS-25D engines of the core stage of their new Space Launch System booster has been postponed.

Four clean burns: the four RS-25D engines under thrust during the initial Hot Fire Test. Credit: NASA

The initial Hot Fire Test, held on January 16th, was expected to last for the full eight minutes the motors would be expected to run during a launch, but was abruptly cut short after just over a minute (see: Space Sunday: SLS roars, LauncherOne flies and a mole dies). Because of this, a further test had been planned for Thursday, February 25th; however during checkout preparations for the test, a  valve  – unrelated to the initial test problems – was found to be “not working properly”, prompting the postponement.

Whether or not the valve will requirement replacement has not been made clear. At the time of writing, no alternate date for the test had been announced, nor had any statement been made whether or not the Hot Fire Test will impact the target date for the first SLS flight, Artemis-1, and which is currently due to take place at the end of 2021.

The Blue Origin New Glenn. Credit: Blue Origin

It has also been announced that Blue Origin’s New Glenn heavy lift launch vehicle will now not fly until the end of 2022 – roughly a year later than its maiden flight had originally been planned.

Designed to lift 50 tonnes to low Earth orbit – giving it roughly the same capability as the SpaceX Falcon Heavy, New Glenn is, like that rocket and the Falcon 9, designed to be semi-reusable.

The decision was made to delay the launch on February 25th. There is no technical issue behind the decision. Rather, it is came as a result of Blue Origin – owned by Amazon’s founder, Jeff Bezos – learning that the US Space Force opting not to select New Glenn as a candidate for the National Security Space Launch (NSSL) Launch Services Procurement, thus allowing the company more time to develop the launcher and all of its support systems.

New Glenn (centre) compared with SpaceX Falcon 9 and Heavy boosters and the ULA Delta rocket (l) and NASA’s Saturn V and SLS variants (r). Credit: unknown

Also on February 25th, Virgin Galactic announced that it is suspending further flight tests of its sub-orbital SpaceShipTwo spaceplane to allow more time for ground-based testing  of new electronics shielding.

On  December 12th, 2020, the SpaceShipTwo vehicle VSS Unity was participating in a sub-orbital test flight when its single rocket motor shut-down a second after igniting, forcing the flight drew to glide back to a safe landing. Telemetry from the flight revealed that the shut-down was the result of electromagnetic interference (EMI) causing the flight computer to re-boot as the engine was ignited.

Since then, the company has been working to increase the shielding around the vehicle’s electrical and electronic systems to better protect them from EMI (which can come from a variety of sources). However, testing of the improved shielding has revealed some of the vehicle’s are still susceptible to EMI, prompting further modifications and additional ground-based testing.

VSS Unity drops clear of its carrier aircraft VMS Eve during s 2020 test flight. Credit; Virgin Galactic

This means that the next test flight is unlikely to come before May 2021. After this, it is expected there will be two further test flights, one with a fully load of passengers – Virgin Galactic employees – and the other carrying the company’s founder and CEO, Sir Richard Branson.

These last two flights are expected to take place over the summer of 2021. They will be followed by the first revenue-generating flight for the system. This will be for the Italian Air Force and will feature three payload specialists flying a series of research payloads. After this, the way should be clear for tourist flights to commence.

To assist with the latter, March 2021 should see Virgin Galactic roll-out the first of this SpaceShipThree vehicles. These have been designed to be more modular than the SpaceShipTwo design, offering a greater flexibility of use as well as better maintainability and faster between-flight servicing.

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