Space Sunday: Perseverance, SN10, and a little bit more

Part of a 360º panorama of Jezero Crater stitched together from 79 individual images captured by the high-resolution Mastcam-Z right-eye 110-mm zoom camera, captured on the afternoon of Sol 4 (Feb. 22nd, 2021). Credit: NASA/JPL

NASA is continuing to get the Mars 2020 rover Perseverance ready to commence science operations, with the past week has seen a number of milestones achieved – including the rover’s first drive on the surface of Mars.

Immediately following the post-landing check-outs, mission controllers were focused on swapping out the Entry Descent and Landing (EDL) software on the rover for the software that will be central to its surface operations. This work was completed on Friday, February 26th – Sol 8 on Mars for the rover. This paved the way for this week’s check-outs of systems.

On Sunday, February 28th, commands were sent to deploy the Mars Environmental Dynamics Analyser (MEDA). Located on the rover’s mast, this comprises two extensible booms and forms the rover’s “weather station”, a set of sensors that measure temperature, wind speed and direction, pressure, relative humidity, radiation, and dust particle size and shape, provided by Spain’s Centro de Astrobiología.

Created from a series of NavCam images recorded on February 28th, this .GIF reveals the deployment of one of the Mars Environmental Dynamics Analyser (MEDA) booms on Perseverance Mars rover. Credit: NASA/JPL

Following this, on Tuesday, March 12th (Sol 12 for the rover), the robot arm was put through its initial paces.

As with Curiosity, the robot arm on Perseverance forms a key part of its science and physical capabilities. At over two metres in length, it has 5 degrees freedom of movement, and ends with a 45 kg “turret” that carries numerous tools and instruments, including:

For its first use, the arm was extended from its cradle and raised to the vertical before being “wriggled” back and forth to confirm instrument stability. It was then lowered and put through a set of rotational moves (as was the instrument turret), before being returned to its cradle and the turret again rotated in two directions.

Images of the rover’s robot arm being put through a basic set of movements. The white “box” on the turret is the PIXL spectrometer, To the right of that is the sample / drill system and on the far side of the turret relative to PIXL is the SHERLOC / WATSON combination. Credit: NASA/JPL
Tuesday’s first test of the robotic arm was a big moment for us. That’s the main tool the science team will use to do close-up examination of the geologic features of Jezero Crater, and then we’ll drill and sample the ones they find the most interesting. When we got confirmation of the robotic arm flexing its muscles, including images of it working beautifully after its long trip to Mars – well, it made my day.

– Robert Hogg, Mars 2020 rover deputy mission manager

A further significant milestone was marked on March 4th (Sol 14), when the rover made that first drive. While covering less then eight metres, it was enough for the rover to perform a few basic manoeuvres intended to allow the engineering team to check-out the rover’s basic mobility capabilities.

Perseverance wiggles one of its wheels in this set of images obtained by the rover’s left Navigation Camera on March 4th, 2021. Credits: NASA/JPL

Following a set of initial steering turns of the forward wheels (shown above), the rover drove forward 4 metres before turning 150o whilst standing still. It then reversed a further 2.5 metres to park in a new location. While comparatively short and taking 33 minutes to complete, this first drive is a small taste of what is to come. With its improved navigation and auto-pilot capabilities, Perseverance is  capable of covering up to 200 metres in a single day once surface operations commence.

This was our first chance to ‘kick the tires’ and take Perseverance out for a spin. The rover’s six-wheel drive responded superbly. We are now confident our drive system is good to go, capable of taking us wherever the science leads us over the next two years.

– Anais Zarifian, Mars 2020 rover mobility test bed engineer

This set of images shows parts of the robotic arm on NASA’s Perseverance rover flexing and turning during its first checkout after landing on Mars. These images were taken by the rover’s NavCam systems on March 3rd, 2021. Credits: NASA/JPL

The new parking position gave the mission team an opportunity to look back at the rover’s landing point and examine the surface and how the skycrane motors dispersed dust and regolith. The view also gave the mission team the opportunity to formally name the landing site, as has been done with past missions.

Using a press conference on the rover’s  progress held on Friday, March 5th, members of the Mars 2020 mission team announced the landing site will be known as the “Octavia E. Butler Landing”, named in honour of the African-American science fiction writer, who passed away in 2006.

Whilst not officially recognised by the International Astronomical Union, the body responsible for all official solar system designations, the name reflects the Jet Propulsion Laboratory’s practice of naming key sites for missions after noted scientists and science fiction writers (for example, the Curiosity rover landing site was dubbed “Bradbury Landing” after science fiction author Ray Bradbury, while the mountain it is exploring was dubbed “Mount Sharp” after American geologist Robert P. Sharp).

Depending on how reporting on the initial phases of the rover’s mission is handled by NASA, I’ll continue to update on Perseverance alongside other Mars missions either as a part of Space Sunday, or within a new series I’m debating running. In the meantime, the video below combines views of Jezero Crater captured by the rover’s Mastcam and NavCam systems during the rover’s first week of operations.

SpaceX SN10 Test Flight

Wednesday, March 3rd saw SpaceX successfully launch their Starship SN10 prototype and come very close to making the first successful landing with the design. It also demonstrated the genuine versatility of the company’s Raptor engines.

Starship SN10 re-ignites its three Raptor engines as it descend towards a landing following its flight to 10 kilometres on March 3rd. Credit: SpaceX

This latter point was shown when the planned launch attempt at approximately 20:15 UTC, the three Raptor engines were automatically shut-down less than a second after ignition, and just 0.1 seconds prior to the launch stand clamps releasing the vehicle as a result of “an off-nominal ignition sequence” with all three motors.

On most systems, such an event would trigger an extensive review of the engines to ensure no significant issues had arisen from the rapid start-up / shut-down, potentially delaying any re-try for one or more days. However, with the Raptor systems, SpaceX were able to carry out a series of checks and confirm that with some software adjustments, a further attempt to fly the vehicle could be made within the remaining launch window.

SN10 starts its ascent, March 3rd, 2021. Credit: NASASpaceflight.com

Overall, the abort lead to a 3-hour delay – most of which was due to the need to de-tank the fuel needed for the flight and reload it again as a result of thermal changes while it was in the vehicle’s tanks. With this operation successfully completed, a the vehicle lifted-off a few seconds after 23:15 UTC.

With all three Raptors operating smoothly, SN10 left the land stand to climb tothe planned altitude of 10 kilometres. Along the way, and as fuel was used, two of the engines shut-down to reduce the dynamic stresses on the vehicle due to it only carrying a partial fuel load, and to reduce its overall delta-vee so as not to overshoot its target altitude.

On reaching 10 kilometres, the vehicle went into a brief hover before the remaining Raptor re-vectored its thrust and, with the aid of the reaction control system (RCS), pushed SN10 over to the horizontal, allowing it to commence the familiar skydive, the forward and aft fins maintaining stability.

SN10 during its horizontal aerodynamic descent, March 3rd, 2021. Credit: NASASpaceflight.com

Dropping for some 2 minutes, the vehicle entered the most critical part of the flight, at around one kilometre above the ground. At this point during the two previous flight tests that two of the Raptor engines re-ignited so that they could rotate the vehicle back to the vertical and allow it to make a tail-first landing. However, SN8 suffered a tank pressurisation issue that caused one of its engines to fail, while SN9 suffered an engine re-ignition failure, and both then crashed into the landing pad and were destroyed.

SN10, therefore, initially re-lit all three of its Raptors, with two of them gimballing to provide the necessary thrust to perform the “flip up” manoeuvre, with the third shutting down as the manoeuvre was completed. A second engine then shut down once the vehicle confirmed it was able to slow itself for landing with just one remaining engine firing.

SN10 then descended smoothly towards touch-down, but video footage suggests that some of it six landing legs failed to deploy, leaving the vehicle canted over following what appeared to be a successful landing. It also appeared to be venting methane fuel, causing a fire suppressant system to one side of the landing pad to start spraying the pad and the base of the vehicle with water.

At this point, the SpaceX official video broadcast ended, declaring the flight a complete success. However, other streams such as NASASpaceflight.com kept running, and so caught the moment when, just over seven minutes after landing, fuel and vapours possibly trapped inside the engine skirt exploded, propelling the vehicle back into the air to fall to is destruction on the pad.

An official statement on the explosion has yet to be given, together with clarification on whether or not some of the landing legs failed has yet to be made. However, while it did end with a bang and what SpaceX call a “rapid unplanned disassembly”, SN10 is the most successful Starship prototype flight to date, and it paves the way for SN11, the last of this generation of prototype vehicles, to make its flight, possibly before the end of the month.

Rapid Round-Up

Boeing Starliner Flight Further Delayed

On Thursday, March 4th, NASA and Boeing jointly announced that the planned 2nd flight of the Boeing CST-100 Starliner vehicle, intended to fly crews to and from the International Space Station alongside the SpaceX Crew Dragon, is to be further delayed.

The uncrewed flight, called Orbital Flight Test 2 (OFT-2), should see a Starliner vehicle launch from Kennedy Space Centre and make an automated rendezvous and docking with the International Space Station (ISS), before making a return to Earth. A similar flight, OFT1 in December 2019, had to be curtailed without the ISS rendezvous and docking after a software error left the vehicle in the incorrect orbit and with insufficient fuel to reach the space station.

The OFT-2 Starliner vehicle mated to is service module in Boeing’s Starliner processing facility at Kennedy Space Centre. Credit: Boeing.

Originally, OFT-2 had been due to fly on or around March 25th, but was pushed back to April 2nd due to avionics on the vehicle having to be swapped out. However, the April 2nd launch has now been postponed due to a combination of delays in completing the pre-flight verification and validation analysis, and because of the high volume of traffic at the ISS (2 Russian Progress resupply vehicles, one American Cygnus resupply vehicle, a Russian Soyuz vehicle and a Crew Dragon).

No new date has been given for the launch, although Boeing have indicated they will not be ready until late April – and that potentially then brings OFT-2 into conflict with the launch of the 2nd Crew Dragon flight that is due to launch to the ISS with four astronauts aboard on or around April 22nd.

Apophis Passes Earth, Getting Ready for 2029 Close Flyby

March 5th 2021 saw 99942 Apophis, the 370 metre diameter near-Earth asteroid that has been the subject of concern since its discovery in 2004, pass safely – and relatively distantly – by the Earth.

Orbiting the Sun every 324 days, the asteroid frequently crosses Earth’s orbit, leading to concerns immediately after its discovery that it could either strike Earth or the Moon in either 2029 or 2036. Given its size and mass, an impact with Earth could be especially devastating. However, refinements in track the asteroid’s orbit removed any risk of impact, although Apophis will come to within 31,600 km of Earth in 2029 –  that’s closer than some satellites orbit the planet.

A computer model show the passage of 99942 Apophis on April 13th, 2029. The blue dots represent satellites in orbit around Earth and the pink line the orbit of the International Space Station. Credit: NASA/JPL

The March 5th passage saw Apophis pass across Earth’s orbit at a distance of some 16.4 million km from the planet – or 44 times the distance of the Moon from Earth. Its passage allowed astronomers to further refine the asteroid’s orbital track, all but eliminating to further threats of impact in 2066 and 2068.

China to Build Super-Heavy Launch Vehicle

China looks set to commit to building a super-heavy launch vehicle that will rival all current and in-development launch vehicles.

The Long March 9 rocket was first proposed in 2018, and on March 3rd, Jiang Jie, one of China’s senior space vehicle engineers, indicated on state media that the vehicle is to be a part of China’s 14th five-year development plan, and is seen as crucial to the country’s lunar and Mars ambitions. When completed, the vehicle is expected to be able to lift up to 140 tonnes to low-Earth orbit or 50 tonnes into a trans-lunar injection and close to that amount to Mars. These capabilities put it on a par with NASA SLS block 2 launch vehicle, and the SpaceX Super Heavy / Starship cargo combination.

China’s Long March 9 compared to other past, present and proposed super-heavy launch vehicles. Via Wikipedia

However, the vehicle faces some technical challenges for China, including breakthroughs in both fabrication large diameter structures and a new generation of high-thrust engines: Long March 9’s core stage will be 10 metres in diameter and powered by four dual nozzle engines capable of 500 tonnes of thrust apiece.It will also require 4 strap-on liquid-fuelled boosters which will likely be developed using the core stage of the Long March 5 launch vehicle. As such, the first flight of the rocket is not expected before 2030.

At the same time, China is set to develop a new generation of crewed launch vehicles that will also be based on the Long March 5 core stage, and which are expected to enter use around the same time at the super-heavy Long March 9.

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