Space Sunday: collisions, storms, aspirations and servicing

A high resolution image of Dimorphos made by stacking the last images received from DART. Credit: Eydeet on Imgur.

On Monday, September 26th 2022, NASA’s DART (Double Asteroid Redirection Test) spacecraft, massing 570 kg slammed into the 160-m  diameter, roughly 5 million tonne asteroid Dimorphos as the latter orbited its parent asteroid, Didymos.

As I outlined in my previous Space Sunday update, the aim of the mission was to test the ability of a vehicle launched from Earth to alter the orbit of a near-Earth object (NEO) purely through the transfer of kinetic energy, in order to prevent a collision between planet and NEO.

Didymos / Dimorphos are NEOs. They orbit the Sun every 2.11 years, hopping across the orbit of Earth in the process and swinging out as far as the orbit of Mars before heading back towards the Sun, Didymos and Dimorphos are ideal subjects for such tests because the former’s orbit around the Sun can be accurately tracked, as can the latter’s near-circular 11.9 hour equatorial orbit around Didymos.

Images of Dimorphos captured simultaneously by the Hubble (l) and James Webb (r) Space Telescopes several hours after DART struck the asteroid. These images mark the first time the two observatories have taken simultaneous images of the same target. and show the spread of material ejected materials  Credit NASA, ESA, CSA, and STScI

At the time of impact, DART was travelling at around 22,530 kmh, and its impact with the asteroid was described as the equivalent of “a golf cart ramming into the Great Pyramid of Giza”.

Prior to the impact, NASA indicated they expected the head-on collision between spacecraft and asteroid should slow the latter’s orbital velocity around Didymos by around 1% – or 10 minutes. This might not sound a lot, but it should result is a clearly observable change in Dimorphos’ orbit.

The impact was observed from a number of vantage points – including aboard DART itself, thanks to DRACO, the Didymos Reconnaissance and Asteroid Camera for Optical navigation, which recorded the spacecraft’s approach all the way up to impact (and loss of signal), a host of ground-based telescopes and both the Hubble and James Web space telescopes.  In addition, a fly-by cubesat called Light Italian CubeSat for Imaging of Asteroids (LICIACube) built by the Italian Space Agency and released by DART roughly two weeks prior to the impact, should be returning post-impact images of Dimorphos in the next few days.

An animation of images captured by the Hubble Space Telescope following the DART impact with Dimorphos, showing the spread of ejecta following the strike. Credit: NASA, ESA, CSA, and STScI

While scientists know a reasonably amount of the orbits of Dimorphos and Didymos, there is far more that is not known about either – such as their overall composition. As such, what would happen as a result of the impact was also unknown – and as seen from the likes of Hubble and James Webb and telescopes on Earth, the impact appeared much brighter than had been expected.

In particular, Hubble and JWST were both able to monitor and image the ejecta generated by the impact. Being able to do this is an added science goal for the mission, as analysis of the streaks of ejecta captured in both visible and infra-red wavelengths will help determine the asteroid’s likely composition and structure.

However, it is still going to be a while for the overall results of impact to be fully calculated, although initial estimates of the change in Dimorphos’ orbit might be known within a week or two following the collision.

China’s International Aspirations

China is looking to build partnerships for its upcoming missions to the moon and deep ventures into the solar system, while omitting mention of (current?) main partner Russia.

Speaking at the International Astronautical Congress (IAC) in Paris on September 21st, 2022, Wang Qiong of the Lunar Exploration and Space Engineering Centre under the China National Space Administration (CNSA) stated that China was open to proposals for science payloads aboard its Chang’e-7 lunar south pole orbiter / lander mission, and the Chang’e-8 in-situ resource utilization test mission, as well as already having the participation of Sweden, Pakistan, the UAE (in the form of a small rover) and the European Space Agency (ESA) for the 2024’s Chang’e-6 mission.

In addition, China is working on a number of deep space missions for which international co-operation is welcomed in the form of:

  • Tianwen-2 (2025), a near-Earth asteroid sampling mission which will also visit a main belt comet.
  • Tianwen-3, a Mars sample return mission.
  • Tianwen-4 (2029) a mission to Jupiter (with a fly-by Uranus).

Finally, China is looking for further partners in the International Lunar Research Station (ILRS) programme to establish a permanent robotic and later human-occupied moon base in the 2030s.

However, the presentation avoided mention of China’s current partner in ILRS: Russia. Per an agreement signed in June 2021, China and Russia are nominally equal partners in the project, and up to Russia’s invasion of Ukraine, ILRS was referred to as a joint China-Russia programme (Russia was not represented at the IAC due to their on-going aggression in Ukraine).

It’s not clear if the conspicuous absence of Russia from China’s presentations signifies sensitivity to the situation in Ukraine and Russia’s isolation, or a change in Chinese thinking towards their engagement with Russia – although there is speculation the latter is the case.

Be it in space or elsewhere, China has a very realistic view of Russia and partnering with Moscow has never been Beijing’s most preferred outcome, for the two countries are not natural partners. This uneasiness is well reflected in their joint ILRS, which still remains little more than a coordination mechanism rather than a bold undertaking sharing a common goal. In moving forward, however, Beijing now seems to be increasingly confronted with a difficult dilemma: turn the relationship into a real partnership or drop it altogether.

– Marco Aliberti, European Space Policy Institute (ESPI)

Thus, given Russia’s current standing in the world, a partnership with Moscow could limit China’s ability to attract new, potentially more auspicious, international partner.

In Brief

Artemis 1

It now appears that the first launch of NASA’s new Space launch System rocket in the Artemis 1mission is unlikely to occur prior to November 2022 – although speculatively, the mid-to-end of October launch window remains possible.

Thanks to the arrival of hurricane Ian, NASA was forced to roll the massive rocket and its launch platform back the Vehicle Assembly Building (VAB) at Kennedy Space Centre overnight on Monday, 26th, / Tuesday, 27th September 2022 in what was (literally, given roll-back commenced at 23:00 local time on the 26th) a 11th hour decision.

As a result of the roll-back, NASA has opted to replace the batteries on the vehicle’s flight termination system (FTS) – the package which destructs the rocket should it veer off-course during its ascent through the atmosphere.

A dramatic shot of Artemis 1 arriving at the Vehicle Assembly Building shortly after 7:00am local time in Florida on Tuesday, September 27th, 2022, even as the weather front of Hurricane Ian moves in. Credit: Greg Scott

This is a non-trivial task, and given the technicalities involved, NASA managers have indicated getting the work completed and returning the rocket to the pad before the end of October could be difficult.  Should the launch slip into November, opportunities for that month exist from November 12th through 27th.

Crew 5

Hurricane Ian has also impacted the NASA / SpaceX Crew 5 ferry mission to the International Space Station (ISS). The 4-person crew – comprising NASA astronauts Nicole Mann and Josh Cassada together with Japanese astronaut Koichi Wakata and Russian cosmonaut Anna Kikina – had been scheduled for October 3rd, but has been pushed back to October 5th as a result of the storm.

The Crew 5 Dragon vehicle and its Falcon 9 booster being prepared at the SpaceX facilities, Pad 39A, Kennedy Space Centre. Credit: SpaceX

This is something of a historic mission – Mann will be the first woman to reach space, and Kikina will be the first cosmonaut to fly to the orbiting lab with SpaceX.

Hubble: NASA and SpaceX Consider Dragon Servicing Mission

NASA and SpaceX are carrying out a study to see if it would be possible to use the latter’s Dragon vehicle to reach the Hubble Space Telescope (HST) and boost its orbit – and, if Crew Dragon is used, deliver a crew to HST to carry out basic, but essential servicing.

From its launch in 1990 through until 2011, HST had to be routinely visited by the space shuttle to allow astronauts carry out essential servicing and the replacement of aging parts, as well as use the shuttle’s reaction control system to periodically raise Hubble’s orbit around the Earth.

NASA and SpaceX are studying the feasibility of using the latter’s Dragon vehicle to boost the Hubble Space Telescope’s orbital altitude, and possibly deliver a crew to Hubble to carry out servicing operations. Credit: NASA

However, in 2011, the shuttle was retired, leaving NASA without a vehicle capable of servicing the observatory, was has lowered its orbit by some 60km compared to when it was launched as a result of atmospheric drag. Unless countered, this drag will continue until HST will tumble uncontrolled into the denser atmosphere and break-up in the mid-2030s. To avoid this, NASA is planning a controlled de-orbit mission to HST using an automated vehicle in 2029/30, ensuring it burns-up safely and any surviving debris falls into the Pacific Ocean. By contrast, should a servicing / orbital boost be possible with Dragon, then Hubble’s operational life could be extended by up to 20 years.

Even so, such a mission by Dragon – crewed or otherwise – will be easy; as noted, HST is specifically designed to be services by the space shuttle, and while a capture mechanism was installed during the very last shuttle servicing mission to Hubble, it is intended to be used as a part of the de-orbit mission mentioned above. But should the study show a Dragon-based boost / service mission is feasible, it could come at little to no cost to NASA.

This is because billionaire Jared Isaacman, who has already financed and commanded the Inspiration4 mission and who is financing a series of further crew flights on Crew Dragon under the Polaris project, has indicated he believes a mission to Hubble would be a worth goal for Polaris – and he is actively involved in the study.

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