Space Sunday: an “existential” rocket, Mars, and a bit on JWST

The Astra LV0006 launch literally goes sideways…

On August 28th, 2021, Astra Aerospace attempted to make the fourth launch of its Rocket 3 vehicle designed to place payloads of up to 150 kg to Sun-synchronous orbits 500 km altitude.

After two unsuccessful and one partially-successful flights of the launch system, it was hoped that this flight, carrying an instrumentation payload for the United States Space Force under the Space Test Program (and which was not designed to separate from the launch vehicle), would be a complete success.

Lift-off from Pacific Spaceport Complex – Alaska on Kodiak Island (high northern latitudes being ideal for polar orbital launches) came at 22:35 UTC, and it was immediately clear the rocket was having something of an existential moment, experimenting with moving sideways away from the launch pad, rather than upwards.

After almost 20 seconds of moving thus, the vehicle decided that “up” was perhaps the better option, and proceeded to climb into the sky, performing more-or-less perfectly through an ascent to 50 km altitude, successfully passing “max-Q” (the period when a launch vehicle experiences the maximum dynamic pressures across its frame) in the process and throttling to full power in a press for orbit.

Sadly, due to the post-lift-off incident, the vehicle had exceeded its range safety limits, risking passage over populated areas on mainland Alaska. The order with therefore given to shut down the first stage motors let it crash back into the sea.

Subsequent analysis of data suggests that one of the 5 Astra-built Delphin motors powering the rocket’s first stage failed at launch, likely resulting in off-centre thrust that caused the vehicle to strike one of its launch mounts, resulting in the sideways tilt and motion. However, despite the loss of the vehicle, the fact that it autonomously recovered to make a successful ascent to a point where, but for range safety concerns, it would likely have achieved a successful orbit, is seen as a remarkable testament to the rocket’s guidance and flight control systems.

Further launches will be pending a complete view of this flight.

Mars Updates

The Mars 2020 rover Perseverance is getting ready to make a second attempt to obtain rock samples for analysis and storage.

As I recently reported, a first attempt at sample gathering didn’t end successfully when it was discovered after-the-fact that the rock selected for the sample was made up of material too fine to be retained within the rover’s drill / sample mechanism following drilling.

Abandoning that attempt, the rover was directed to travel 455 metres to a small ridge dubbed “Citadelle”, where it will now attempt to gather a fresh sample. The area was selected as it appears to be able to withstand erosion by the Martian wind better than the surrounding ground, and has a number of interesting rock formations in it.

A look at the rock dubbed “Rochette” (image centre) at the “Citadelle” ridge that has been selected as the next target for an attempt by Perseverance to gather samples for analysis / caching. This image was captured on August 26th, 2021. Credit: NASA/JPL

In order to help ensure a sample has been collected post-drilling, a new step has been introduced into the process: once drilling has been completed, the arm and turret will be raised and positioned to allow the rover’s MastCam-Z cameras to image as a visual confirmation that there is material within it. Once confirmed, processing of the sample tube through to the rover’s on-board storage area will then be allowed.

Nor has the first “empty” tube been an entire waste – it now contains a sample of pristine Martian atmosphere, something the mission had intended to collect at some point, and so it will form a part of a sample cache of tubes the rover will at some point deposit on the surface of Mars in anticipation of collection by a future sample return mission.

While atop Citadelle, Perseverance will use its subsurface radar, called RIMFAX – the Radar Imager for Mars’ Subsurface Experiment – to peer at rock layers below it. The top of the ridge will also provide a great vantage point to look for other potential rock targets in the area.

NASA has also confirmed the next mission to Mars, due to be launched in 2024. In keeping with the agency’s approach to alternating surface missions with orbital missions, it has approved the ESCAPADE mission of twin satellites for launch in 2024.

Led by the University of Berkeley, California, the Escape and Plasma Acceleration and Dynamics Explorers mission is a relatively low-cost (under US $80 million including launch costs) attempt to put two small satellites, dubbed “Red” and “Blue” into orbit around Mars to further study the Martian atmosphere and its interactions with the solar wind.

An artist’s impression of the ESCAPADE satellites approaching Mars. Credit: NASA

The satellites will be launched using two Rocket Lab Electron rockets, with the company’s Photon satellite bus used to protect / power them during a low-energy, 11-month cruise to Mars. This marks a significant increase in Photon’s capabilities, the bus originally having been designed to support the launch of satellites into Earth or cislunar orbits. As such, the mission is seen as a “high risk” venture – but as the team behind ESCAPADE note, most missions to Mars come with a price tag of US $800 million or more, and roughly a 90-95% chance of success in reaching Mars / Mars orbit. ESCAPADE is estimated as having an 80% chance of success in doing the same – but at one-tenth the cost, thus making the increased risk in using Rocket Lab systems worth the effort.

Once in orbit, the mission will collect data that could help reconstruct the climate history of Mars and determine how and when it lost its atmosphere. ESCAPADE also will study the ionosphere of Mars, which can interfere with radio communications on the surface and between Earth and Mars colonists. Finally, with simultaneous two-point observations of the solar wind and Mars’s ionosphere and magnetosphere, ESCAPADE will provide a “stereo” picture of this highly dynamic plasma environment in the planet’s upper atmosphere.

And when it comes to human missions to Mars, a new study from the University of California Los Angeles proposes a novel way of reducing the impact of radiation during the journey to / from Mars: by launching during periods of high solar activity, notably the periods immediately following that of solar maximum, when the Sun is at its most active. While launching missions during periods of high solar radiation to reduce the risk of radiation exposure might sound counter-intuitive, there is some logical to the idea.

Simply put, interplanetary missions face two radiation risks – solar, which can be reasonably well mitigated against in a variety of ways (but not entirely avoided or made “safe”) and galactic cosmic rays (GCRs), which are considerably harder to deal with, and more devastating in their impact. However, during periods of high solar activity, the more energetic solar radiation actually deflects GCRs away from the solar system. So the UCLA study suggests that by launching crewed missions in the years immediately following a period of solar maximum could massively reduce exposure to GCRs without significantly increasing the risk from solar radiation.

Just how practical it would be to restrict missions to Mars to certain time frames within the Sun’s 11-year cycle is debatable. If we are to practically explore and possibly establish a permanent presence on Mars, missions will need to be a lot more frequent; so more practical research into things like garment materials, materials used in space vehicle design, etc., that could help mitigate both primary and secondary radiation would likely be far more practical. However, the bright spot in the UCLA study does suggest that if missions are kept to below 4 years duration, then radiation exposure could be seen as “acceptable” – and currently, the more favoured “opposition” class of mission of 2.5 to 3 years duration falls inside that limit.

James Webb Ready to Head to Launch Site

After years of delay, the massive James Webb Space Telescope (JWST) is now being prepared for its journey to meet its launch vehicle for integration and final launch preparations.

The deep space telescope completed its final ground testing in California in mid-August and will shortly departed by sea for a trip through the Panama Canal to reached the European Spaceport at Guiana Space Centre, Kourou in French Guiana, South America.

The James Webb Space Telescope (JWST). Credit: NASA

Whilst built in the US, the JWST is an international project involving 14 countries and 29 states, with the United States and the European Space Agency meeting the largest portions of the costs and sharing responsibilities for the telescope’s launch and operations.

Although the telescope is the last part of preparations for it to commence its trip to the launch site, the main stage of its Ariane V launch vehicle is already at the spaceport, whilst the rocket’s modified upper stage, on which JWST will be mounted for the launch, started on its way by ship from Europe to French Guiana on August 17th, travelling with several other elements of the launch vehicle.

JWST’s trip to the L2 position on the far side of Earth relative to the Sun. Credit: NASA/GFC

Once at the launch site, the telescope will undergo post-transport checks on its systems and have its overall condition assessed. It will then be integrated with the Ariane V upper stage – which will both protect it and boost it on its way from Earth to its operational environment at the Earth-Sun L2 position – and the pair then mated to the Ariane launcher’s main stage.

Launch of the telescope is expected to be in late November / early December 2021. It will take 16 days to reach the L2 position, some 1.5 million km from Earth, deploying its primary mirror and its solar shield (needed to cool and protect its systems and instruments from the Sun’s heat and radiation, and keep the primary mirror in shadow) and other key systems along the way.

On arriving at the L2 position, JWST will enter a halo orbit within it, designed to minimise the used of limited on-board propellants. Assuming all this goes to plan, a 6-month check-out / commissioning period will follow, before the telescope commences operations around mid-2022. Overall, it is hoped the telescope will operate for between 5 and 10 years, at which point it will have exhausted its propellant reserves and so will not be able to maintain the correct orientation for communicating with Earth, and will likely be shut down.

China Looks to Space Structures in the Kilometre Scale

Building something the length of Battlestar Galactica – said to be around 1.4 km in length in the Ronald D. Moore reimagined series of that name – might sound a tall order when it comes to the technologies available to us today, but it is something the National Natural Science Foundation of China (NNSFC) is looking towards, having just launched a 5-year programme of studies into the feasibility of building mammoth structures in Earth orbit.

The focus of the study is on the development of ultra-strong, ultra-lightweight materials to be used in Earth-based fabrication of elements to be used in the orbital construction of structures such as solar power satellites and very large orbital habitat / farming / industrial facilities, all of which are seen as key goals for the Chinese space programme – and even the development of large interplanetary craft to be used in support of human missions to Mars.

Kilometre-scale, ultra-large spacecraft are a major strategic aerospace equipment for the future use of space resources, exploration of the mysteries of the universe, and long-term habitation in orbit.

– CNSF report, August 2021

There have been many ideas over the decades for massive orbital facilities, from solar power satellites to entire colonies such as the dual O’Neill Cylinder (above). Whilst China’s new study is definitely not in this class of structure (32 km in length!), it is aimed towards a better understanding of the issues in building ultra-large structures without a reliance of exotic solutions (lunar mass drivers, harvesting asteroids, etc), and trying to mitigate them, Credit: G. Clovis

China has already built a reputation for its space ambitions, including crewed missions to Mars and establishing a permanent presence on the Moon. The country has even started dedicated research in solar power satellites – capturing sunlight and then beaming it as microwaves to receiving stations on Earth. The China Academy of Space Technology (CAST), for example, is already constructing test facilities in the Chongqing area for space-based solar power, aiming to carry out small-scale electricity generation tests in 2022, building towards megawatt-level power generation energy production by around 2030.

Such means of energy production are not without potential issue (you would not want to stray into the invisible beaming of high-energy microwaves, for example, and their impact on local weather and atmospheric conditions isn’t well understood). However, developing such a capability is seen as a means of replacing China’s need for coal, oil, and gas in energy production.

It is not anticipated that any significant projects will come directly out of the NNSFC study (although it will provide funding for up to 10 individual research activities by a range of organisations in China) – it is hoped the results will help inform more of China’s long-term space ambitions and goals.