Space Sunday: aerial views, infra-red images & a few notes

Debris Field From the Mars 2020 mission entry, descent and landing (EDL) systems as seen by the Ingenuity helicopter drone during its 26th flight on April 19th, 2022: to the left, the shattered backshell that helped protect rover and helicopter during entry in the Martian atmosphere. and to the right, the collapsed supersonic parachute that slowed the descent to subsonic speeds. Credit: NASA/JPL

Ingenuity, the Mars 2020 mission’s helicopter drone completed its 26th flight on April 19th, and it was something very special, as NASA revealed in a mission update published on April 27th.

As I reported in a recent Space Sunday article, the Mars 2020 rover Perseverance passed close to where its aeroshell – called the backshell – and the parachute used during the descent through the Martian atmosphere had landed after the rover and its rocket-powered skycrane had departed, and was able to image both from a distance at ground level. For its 26th flight, Ingenuity was tasked with flying over and around both backshell and parachute and taking a series of images.

Graphic showing the Mars 2000 EDL – entry decent and landing – and the use of the backshell and parachute. Credit: NASA/JPL

During the mission’s arrival on Mars in February 2021, both the aeroshell and the parachute performed vital roles. The former protected the rover and skycrane from the heat generated through the entry into Mars’ atmosphere and its supersonic descent, whilst the latter slowed that supersonic descent to subsonic speeds, allowing the rover and its rocket-propelled skycrane to drop free and fly clear.

Once separated, the backshell and parachute continued their descent and, in a very practical demonstration on why parachutes can only do so much in the tenuous atmosphere, reached the ground still travelling at an estimated 126 km/h. Hence while the conical backshell appears to have burst apart on impact.

The Mars 2020 mission backshell and supersonic parachute seen from Ingenuity as it traverses over the debris zone, April 19th, 2022. The black object, slight above centre on the left edge of the image is actually part of one of Ingenuity’s landing feet, not part of the backshell debris. This image has also been post-processed to give near-Earth normal lighting and colour definition. Credit: NASA/JPL

Imagining the backshell and parachute not only provides some stunning photographs, it also helps inform engineers on how well the hardware actually worked, and offer insights to help with upcoming missions – such as the Mars Sample Return mission, for which initial testing of elements of the EDL systems recently started.

Getting the images proved a fitting celebration for the first anniversary of Ingenuity’s maiden flight. Stating at 11:37 local time, with the Sun ideally placed to offer the best lighting, the 159-second flight saw the helicopter climb to a height of 8 metres before flying 192 metres to take its first image. It then moved diagonally across the debris zone, hovering to take a further nine images at pre-determined points. It then moved 75 metres clear of the debris field and landed, for a total flight distance of 360 metres, With the flight completed, Ingenuity had clocked up a total of 49 minutes flying time on Mars, with a total distance covered of 6.2 km.

A further view of the Mars 2020 mission backshell and supersonic parachute seen from Ingenuity on April 19th, 2022., seen under Mars daylight lighting. Credit: NASA/JPL

The images reveal the backshell survived its impact surprisingly well, and that its protective white covering also came through entry into the Martian atmosphere with very little heat scarring, while many of the 80 high-strength suspension lines connecting it to the supersonic parachute are visible and appear intact.

Only around one-third of the 21.5 metre diameter parachute is visible, however. Whilst smothered in surface dust, the ‘chute appears completely undamaged by the supersonic airflow during inflation, and it is thought that only a third can be seen because of the way in which it collapsed onto itself after the backshell impacted.

Perseverance had the best-documented Mars landing in history, with cameras showing everything from parachute inflation to touchdown. But Ingenuity’s images offer a different vantage point. If they either reinforce that our systems worked as we think they worked or provide even one dataset of engineering information we can use for Mars Sample Return planning, it will be amazing. And if not, the pictures are still phenomenal and inspiring.

– Ian Clark, Mars Sample Return Ascent Phase Lead

JWST Update

The James Webb Space Telescope has now completed all aspects of aligning the 18 segments of its massive primary mirror and is moving into the final phase of science instrument commissioning.

As I’ve previously reported in these pages, JWST, the most ambitious space telescope yet built, is located at the Earth-Sun L2 position, 1.5 million kilometres beyond the orbit of Earth relative to the Sun. In March the core work of aligning the 18 segments of the primary mirror was completed such that the telescope could capture crystal clear images in the infra-red directly through its optical systems.

However, and  as I noted at the time, the process of commissioning the science instruments on the telescope would likely require further adjustments to ensure the everything is correctly aligned for science image processing. This work was the first formal step taken in the commissioning process for the science instrument suite once it had been powered up and had reached its required operating temperature range, and on April 28th, NASA confirm the month-long process of very fine final adjustments had been successfully completed, and the science team is now ready to move forward into the final phase of JWST’s commissioning: calibrating the instruments.

The optical performance of the telescope continues to be better than the engineering team’s most optimistic predictions. Webb’s mirrors are now directing fully focused light collected from space down into each instrument, and each instrument is successfully capturing images with the light being delivered to them. The image quality delivered to all instruments is “diffraction-limited,” meaning that the fineness of detail that can be seen is as good as physically possible given the size of the telescope. From this point forward the only changes to the mirrors will be very small, periodic adjustments to the primary mirror segment.

– NASA JWST press release, April 28th, 2022

This NASA image contains images from each of the major instruments on the James Web Space Telescope (JWST) to ensure the telescope’s mirrors are correctly aligned to allow all instruments to product perfect images. Credit: NASA/STScI
The completion of the alignment work came with the release of a set of images from each of the telescope’s science instruments, as shown above. These instruments are:

  • The Near Infrared Camera (NIRCam): the primary imager covering the infra-red wavelength range 0.6 to 5 microns. It is capable of detecting light from the earliest stars and galaxies in the process of formation, star populations in nearby galaxies, the light from young stars in our own galaxy, and objects within the Kuiper Belt.
  • The Near InfraRed Spectrograph (NIRSpec): primarily designed by the European Space Agency (ESA) NIRSpec will operate in tandem with NIRCam over the 0.6 to 5 micron wavelengths to reveal the physical properties of objects emitting light at those wavelengths.
  • The Mid-Infrared Instrument (MIRI): also primarily the work ESA, MIRI has both a camera and a spectrograph operating in the 5 to 28 micron wavelengths – longer than our eyes see. As such, it will be able to “see” and reveal the properties of near and distant objects “invisible” to NIRCam and NIRSpec.
  • FGS/NIRISS: technically two instruments supplied by the Canadian Space Agency operating in the 0.8 to 5.0 micron wavelengths:
    • The Fine Guidance Sensor (FGS): allows Webb to point precisely, so that it can obtain high-quality images.
    • The Near Infrared Imager and Slitless Spectrograph (NIRISS) instrument: designed for first light detection, exoplanet detection and characterisation, and exoplanet transit spectroscopy

The final work in calibrating these instruments is expected to take around a month to complete, and will also involve ordering the telescope to point to different deep space targets so that the amount of solar radiation striking its heat shield will vary, allowing the science team to confirm that the thermal stability for the instruments and mirrors is being maintained within the optimal operating temperatures.

A comparison in resolution power between the Spitzer infra-red telescope (2003-2020) and JWST (2022), using the same region of deep space. NASA/STScI / 

As a part of the alignment exercises, JWST was directed to image an area of space that had been used for aligning / calibrating the mirrors and instruments used on the Spitzer Space Telescope (2003-2020). While a direct comparison between Spitzer (with a primary mission diameter of just 85 cm), and JWST (with a primary mirror diameter of 6.5 metres) is little on the “apples and pears” scale, putting the two commissioning images side-by-side does reveal just how much more of the universe JWST will be able to reveal to us.

Short Updates

SpaceX Starship

This is said to be a leaked image taken inside Booster 7 showing the crushed CH4 downcomer, which should be cylindrical.

The Federal Aviation Administration (FAA) has announced a further month-long delay in completing and publishing their Environmental Impact Assessment in proposed Starship operations out of the SpaceX Starbase facilities at Boca Chica, Texas, with the final report now scheduled for release on May 31st, 2022. This means it will by June at the very earliest before SpaceX can proceed with any orbital launch attempt.

However, it now appears that speculation on whether Booster 7 or Booster 8 will be used for that attempt, as mentioned in my previous Space Sunday article received an inadvertent boost just after that article was published.

This was due to a photograph being circulated via social media reportedly showing the downcomer pipe within Booster 7 had collapsed. This is the pipe which feeds liquid methane (CH4) from the upper tank and down through the lower liquid oxygen (LOX) main and header tanks to the rocket’s motors, and so is a key element of the booster.

SpaceX has not commented on the image itself, but it was released shortly after Booster 7 was returned to the Starbase vehicle assembly area from the launch facilities at the start of the week, where an inspection team spent time imaging the interior of the booster’s LOX tanks.

Lab Padre commentator Zack Golden reviewed footage of the last cryogenic load test carried out on Booster 7 prior to the roll-back, and believes he has found the point at which the downcomer failed, publishing his work in a video he’s amusingly called CSI: Starbase, Episode 1. In short, in what appears to have been a procedural error, the CH4 tank was drained and vented too quickly compared to the LOX tanks. This either caused the downcomer to vacuum collapse on its own, or to collapse due to pressures from the surrounding liquid nitrogen in the LOX tank.

Following the inspection of Booster 7, further credence to the downcomer collapse came when new pipe segments were delivered to the high bay now housing Booster 7, suggesting SpaceX might attempt to replace those crushed within the booster. Whether this can be done and whether it will allow Booster 7 to fly, remains to be seen. But as noted, the incident has increased speculation that it will be Booster 8, not 7, that makes the initial orbital flight test.

Axiom AX-1 Returns, Crew 4 Arrives

Crew Dragon Endeavour splashed-down in the Atlantic Ocean on April 25th, bringing to an end the Axiom AX-1 mission, the first all-private mission to the International Space Station (ISS). Initially planned for around 10 days, the mission was extended as a result of poor weather affecting the area of the planned splashdown location off the Florida coast.

Crew Dragon Endeavour splashes down in the Atlantic Ocean off the Florida coast at the end of the Axiom AX-1 mission on April 25th, 2022. Credit: SpaceX

The departure of the mission from the ISS 16 hours prior to splashdown marked the start of a busy period for NASA, SpaceX and Roscosmos.

On April 27th, The SpaceX / NASA Crew 4 mission launched from Pad 39A at Kennedy Space Centre en-route to the ISS carrying NASA astronauts Kjell Lindgren (commander), with Bob Hines (pilot) and Jessica Watkins, together with European Space Agency astronaut Samantha Cristoforetti making her return to the ISS carrying, all aboard Freedom, the newest Crew Dragon capsule to join the fleet. Docking with the ISS took place 16 hours after launch, making the start of a 6-month rotation for the crew.

Crew Dragon Freedom docked as the ISS as a part of the NASA Crew 4 mission. Credit: NASA

The arrival of the mission was squeezed in between two long-planned spacewalks by cosmonauts Oleg Artemyev and Denis Matveev, who have been performing upgrades to the station external systems.

Freedom’s arrival once again brings the crew compliment of the ISS back up to 11, but this will change on May 4th, when – subject to weather off the Florida coast – Crew Dragon Endurance is due to depart the station with the Crew 3 team of Raja Cahri (commander), Thomas Marshburn (pilot) and Kayla Barron, together with ESA astronaut Matthias Maurer. After the Crew 3 departure, attention will turn to the second attempt to test fly an uncrewed Boeing CST-100 Starliner to the ISS. Targeted for launch in mid-May, and if successful, this mission should pave the way for a crewed demonstration flight before the end of 2022, and actual crew ferry missions to / from the ISS to commence in 2023.

Dreamchaser Approaches Completion

Tenacity, the first operational Dream Chaser Cargo space plane designed to carry cargo to / from the ISS, is currently nearing completion at the Colorado headquarters of Sierra Space, the vehicle’s designers and operators.

A forward view of Tenacity, the first Dream Chaser Cargo vehicle, nearing completion, and awaiting its avionics, RCS motors, thermal protection system and outer skin. During launch, the winglet are folded over and against the hull. Credit: Sierra Space

Contracted to fly at least six ISS re-supply missions, with the first due for launch in January 2023, Dream Chaser Cargo will be capable of lifting at least 5 tonnes of materiel to the ISS, split between the vehicle’s own payload area (1.75 tonnes, which can also be used to return equipment and experiments to Earth) and an expendable support / power module called Shooting Star (up to 4 tonnes of internal payload and 500 kg in unpressurised external payload).

Designed to be launched atop any booster with a 5-metre payload fairing, Dream Chaser Cargo is designed to dock with the ISS using a port on the back of the Shooting Star module (and which also gives pressurised access to the Dream Chaser’s cargo bay). Once incoming cargo has been off-loaded to the ISS, items for return to Earth can be loaded into Dream Chaser and the Shooting Star loaded with trash for disposal. After departing the ISS, Dream Chaser will detach from Shooting Star to make a controlled entry into Earth’s atmosphere before landing on a conventional runway. Shooting Star will then burn-up in the upper atmosphere.

A three-quarters rear view of Tenacity under assembly at Sierra Space. The large silver ring is the docking mechanism / hatch that will connect the vehicle with its expendable Shooting Star cargo / power module and provide access to Dream Chaser’s internal cargo space. Credit: Sierra Space

Tenacity is the first in an unspecified number of the cargo variant of Dream Chaser. As work continues on it, Sierra Space is hoping to finalise the development of a crew version (originally prototyped as part of the competition to provide NASA with a vehicle to carry crews to / from the ISS) that they plan to use in conjunction with the proposed Orbital Reef space station the company plan to build with Blue Origin and others, as well as offering as a crew / passenger vehicle for other on-orbit uses.

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