Tag: Astronomy

NASA has rolled out the first of what is intended to be both the first of its new “super rocket”, the Space Launch System, and the vehicle to start the United States and its international partners on the road back to the Moon.

At 21:47 UTC on March 17th, the huge rocket, mounted on its mobile launch platform, slowly crept out of one of the high bays of the Vehicle Assembly Building (VAB), the iconic cube sitting within NASA’s Kennedy Space Centre which was used as an integral part of Project Apollo and which is now fulfilling a similar role for Project Artemis, on the back of a massive crawler-transporter at the start of a 6.72 km journey to Kennedy Space Centre’s Lunch Complex pad 39B.

It was not a swift journey, taking some 11 hours to complete  – albeit with stops along the way for checks to be carried out – the crawler-transporter finally reaching the top of the incline of the launch pad 04:15 UTC on Friday, March 18th.

The move of the rocket from VAB to pad was not in readiness for the launch of Artemis 1 – the mission this SLS vehicle will carry to orbit – but rather for the final series of tests to be carried out on the fully integrated rocket and its Orion Multi-Purpose Crew Vehicle (MPCV) payload to ensure both are ready for that launch, which is currently set for a provisional window in mid-May 2022.

As I noted in my last Space Sunday update, the focus of these tests will be a full wet dress rehearsal, due to take place in April. This will see the rocket fully fuelled and go through a full launch countdown that will stop just nine seconds prior to an actual launch. The intention is to make sure everything with the rocket, the payload and the launch systems are all ready for a launch attempt, and will be followed by a further 8-9 days of additional pad tests. After this, the rocket will be returned to the VAB and assessed ready for final flight clearance.

When it does take flight, SLS will become the most powerful launch system built by NASA. The Block 1 vehicle being capable of delivering up to 95 tonnes to low Earth orbit, and the upcoming Block 1B up to 105 tonnes, and the future Block 2 vehicle up to 130 tonnes – putting it in the same lifting class as SpaceX’s Starship / Super Heavy launch system, but potentially far more flexible in turns of specialised launches, SLS being capable of launching smaller payloads (e.g. 23-45 tonnes, depending on the launcher variant) directly to the Moon, or other payloads out into the solar system without any need for on-orbit refuelling.

However, as I’ve noted before, there are some significant cost issues for SLS that may impact its use, the most notable being that of ongoing costs. Development work on the SLS system has thus far eaten US $23.01 billion, and while NASA would claim a lot of that (US $14 billion) has gone directly into work creation, it nevertheless means that as a non-reusable system, SLS is terribly expensive: NASA’s own Office of Inspector General (OIG) estimates each launch will cost some US $4 billion, twice NASA’s launch cost estimate, and will never fall below US $1 billion as the agency has suggested.

This cost factor has already seen NASA turn to other launch systems for missions originally earmarked for SLS. The Europa Clipper mission, for example, has been move to a SpaceX Falcon Heavy launcher on the ground of launch costs (and the fact that SLS generates so much vibration at launch, it is unsuitable to fly certain sensitive instruments into space).

As it is, five SLS missions in support for Artemis have thus far been confirm, with vehicles for three more after Artemis 1 already under construction:

• Artemis 1: uncrewed mission to cislunar space to test the Orion MPCV; duration: some 25.5 days – mid 2022.
• Artemis 2: crewed mission to lunar orbit; duration: 10 days – 2024.
• Artemis 3: crewed lunar obit / lunar landing mission; duration:30 days – 2025/26:
• Artemis 4: crewed mission to a lunar near-rectilinear halo orbit (NRHO) in support of the Lunar Gateway station and the core I-HAB deployment – 2026/27
• Artemis 5: crewed mission to a lunar near-rectilinear halo orbit(NRHO) in support of the Lunar Gateway station and the European System Providing Refuelling, Infrastructure and Telecommunications (ESPRIT) module, together with a lunar surface mission – 2027-28.

Starship HLS: NASA Updates

A further key component for Project Artemis is the Human Landing System (HLS), the vehicle that will be used to transfer crews between lunar orbit and the surface of the Moon and (initially) provide them with living space whilst on the Moon. Currently, only one contract has been issued for HLS, and as I’ve noted before, it is to SpaceX for the use of a lunar variant of their Starship vehicle, although the agency has more recently been order to acquire HLS vehicles from other sources.

Coinciding with the SLS roll-out at Kennedy Space Centre, NASA issued an update on the SpaceX HLS programme, including the work going into some key elements, such as the elevator that will carry the 2-person crew of Artemis 3 the 30-40 metres down the side of the vehicle to the Moon’s surface and back after landing, together with the airlock through which they’ll leave / enter HLS during surface operations and some of the living / working facilities inside the vehicle.

The update also confirms that HLS will require some six starship / super heavy launches:

• The launch of a special “tanker” Starship that will be parked in Earth orbit and used for a wide range of Starship propellant transfer operations.
• Four further launches of re-usable Starship vehicles equipped with additional fuel tanks that will carry propellants to be transferred to the orbital “tanker”.
• The HLS starship itself and the cargo needed for Artemis 3. This will dock with the “tanker” and take fuel from it that can be used to boost the HLS vehicle to lunar orbit and to both land it on the Moon and then get it back to lunar orbit.

Once the HLS is in lunar orbit, the 4-person Artemis 3 crew will then launch to the Moon aboard an Orion MPCV lifted by SLS, and rendezvous with HLS so two can transfer to it and then travel to / from the lunar south pole. After transferring back to Orion, the crew will return to Earth, leaving the HLS starship in lunar orbit, potentially with either fuel to be used by the crew of Artemis 5, the second lunar landing mission.

However, whilst SpaceX HLS is earmarked for this mission (and will likely be the only HLS craft capable of supporting Artemis 5 in 2027/28), some in Congress are pushing NASA to use an alternative HLS design for the second lunar landing (which is which Artemis 4 was switched from a join lunar gateway / lunar landing mission to being solely a lunar gateway mission.

Continue reading “Space Sunday: a big rocket, a telescope & yellow and blue” →

The James Webb Space Telescope (JWST) is due to enter its initial halo orbit around the Earth-Sun L2 position, 1.6 million kilometres beyond Earth’s orbit around the Sun, on Monday, January 24th, 2022.

With the deployment of its major external elements completed, the observatory has been engaged in the first phase of a sensitive operation to correctly align the 18 hexagonal segments of its primary mirror so it perfectly reflects light into the boom-mounted secondary mirror and thence back into the telescope’s interior for delivery to its space science payload.

This first part of what is an extensive operation saw all 18 segments gently eased 12.5 mm away from the mirror’s backing structure, each segment being propelled forward by six tiny motors, referred to actuators. This allowed each mirror segment to be gently moved away from the restraints that held it in place during launch, and provides enough space behind each segment so it can be gently adjusted to align with its companions as the alignment process continues, all of them coming together to form a single, focused parabola.

When it starts, the latter part of the work will involve the actuators moving in the micron and nanometre ranges of movement, and once started, is expected to continue for around 40 days.

However, before that process begins, at 19:00 UTC on Monday, January 24th, JWST will fire its thrusters to ease itself into its initial halo orbit around the Earth-Sun L2 position, marking its arrival in the area of space where it will operate.

Thanks to the sheer accuracy of the Ariane 5 launch vehicle and the “mid-course” correction thruster burns JWST has made en route to this point, it has been calculated the observatory currently has sufficient propellant reserves for at least 10 years of operations. If the insertion burn proves to be as accurate, mitigating any need for it to be further refined, then JWST may have its overall mission length extended a little more.

Once safety inserted around the L2 point, the telescope will go through an additional period of cooling adjustment to bring its instruments down to their operational temperatures. This process, which will actually use heaters to ensure heat dissipation is properly controlled, will take a number of weeks to complete, after which the primary mirror alignment process will resume, allowing scientific instrument calibration to commence.

Artemis: No Immediate Second Lunar Landing

After landing astronauts on the Moon in the mid-2020s for the first time in more than a half-century, NASA will wait at least two further years before making a second crewed lunar landing as part of the Artemis program.

Artemis 3 is due to deliver a crew of 2 to the lunar surface in around 2025. However, the next mission slated for Artemis will not follow it to the lunar Surface. Instead, and as indicated at a two-day meeting of the NASA Advisory Council’s Human Exploration and Operations Committee on January 18th/19th, it was indicated that the Artemis 4 mission will target the assembly of the Lunar Gateway.

This is the space station that will be placed in cislunar orbit and used as a transfer station for crews arriving from Earth aboard NASA’s Orion capsule and the Human landing System (HLS) vehicles that will carry them to the surface of the Moon and back. The first elements of the Gateway, the Power and Propulsion Element and Habitation and Logistics Outpost, will be launched together via a SpaceX Falcon Heavy in late 2024. They will then spend a year spiralling around the Moon and settling into their halo orbit.

Artemis 4, which will feature the Block 1B Space Launch System rocket using the powerful Exploration Upper Stage (EUS), intended for heavy cargo launches and deep space missions will carry the International Habitat Module (I-Hab) for the gateway, along with a crewed Orion vehicle that will oversee attaching I-Hab to the Gateway modules already in lunar orbit.

Even with the more powerful EUS replacing the Interim Cryogenic Propulsion Stage that will fly on Artemis 1-3, the Gateway flight of Artemis 4 will be a challenge for the SLS. The Block 1B vehicle will be capable of delivering around 38 tonnes to lunar orbit – and some 27 tonnes of that capability will be taken up by the Orion crew capsule and its service module. That means the European and Japanese space agencies, responsible for providing I-Hab for Artemis, must ensure the module masses no more than 10 tonnes. By comparison, similar modules on the ISS average around 12-12.5 tonnes.

A further reason for focusing Artemis 4 on Lunar Gateway activities is that NASA will not actually have any HLS vehicle(s) at its disposal for lunar landings for a period of time after Artemis 3. In awarding the initial HLS contract to SpaceX to develop a lunar landing variant of its Starship vehicle, NASA did so on the basis of using only a single lunar landing. Once it returns to orbit, the SpaceX HLS will require refuelling in order to make a second trip – and currently, NASA has indicated that it would rather await a “sustainable” HLS system  – to be developed under a new, yet-to-be awarded contract called Lunar Exploration Transportation Services (LETS).

Exactly what is so happen to the SpaceX HLS after Artemis 3 is unclear. That mission will not use the Lunar Gateway, but will see an Orion dock with the SpaceX vehicle in lunar orbit for the 2-person crew transfer. As such, it is entirely possible the SpaceX HLS might simply be “parked” in lunar orbit and left.

However, given any LETS contract has yet to be granted a further crewed landing on the Moon under the Artemis banner is unlikely to occur before late 2027 or (more likely) 2028 / 29.

Continue reading “Space Sunday: JWST, Artemis and rockets delivering cargo to Earth” →

The James Webb Space Telescope (JWST) has completed deploying all of its major components whilst en route to its operational orbital position at the Earth-Sun Lagrange L2 position.

At the time of my last update, NASA was expected to start work on tensioning-out the layers of the observatory’s layered sunshield. However, this was delayed in preference of working on JWST’s power subsystem. The decision came as a result of telemetry showing the observatory’s solar arrays were not producing their anticipated output due to them operating at their factory defaults. After re-balancing them, engineers took the opportunity to gather a baseline of power requirements for future reference, and to ensure the motors that are key to the sunshield tensioning process were at their optimal temperatures prior to starting the tensioning operation.

The work on the power subsystem meant that tensioning operations did not start until January 3rd. This comprised each of the hair-thin layers of the sunshield being gently tensioned out and separated from the other layers to allow it to function most efficiently in absorbing / reflecting heat and sunlight. By the end of the 3rd, three of the five layers had been correctly tensioned, putting the operation well ahead of schedule, allowing the operation to be completed with the tensioning of the last two layers on Tuesday, January 4th.

This left the way clear for the deployment of the observatory’s secondary mirror system. Commencing on January 5th,  this involved unfolding a series of booms called the Secondary Mirror Support Structure (SMSS) to extend the secondary mirror assembly out in front of the primary mirror, allowing it to gather and focus the light from the primary back through an aperture at the centre of the primary, where a third mirror reflects it down into the observatory’s interior and to its instruments.

On January 6th JWST deployed the radiator systems that serve to remove excess heat from the observatory. Stowed flat against the rear of the main mirror assembly, the radiator panels were successfully extended out and away from the body of the observatory, freeing the mechanisms required to unfold the two “wings” of the primary mirror.

At 6.5 metres in diameter, and comprising 18 hexagonal gold-covered segments JWST’s primary mirror is too big to fit in the payload fairings of any operational launch vehicle, thus the use of the two “wings” to the port and starboard sides of the mirror.

Work started on unfolding these on January 7th, commencing with the port wing. The operation commenced at 14:30 GMT, the wing unfolding in five minutes  – although latching it into place took a further two hours. A similar operation was then initiated on January 8th to deploy the mirror’s starboard wing, with telemetry received at 18:17 GMT to confirm it had locked into place in its deployed configuration.

The successful unfolding and latching of the primary mirror segments marked the end of the deployment phase of the mission, allowing the JWST mission and engineering teams to move onto the commissioning phase of the mission.

In all, this will take some five months to complete; the first part of which involves correctly align the 18 individual mirrors that make up the observatory’s primary mirror so that they all work in concert to gather and reflect light into the secondary mirror. This is a multi-step process, in which each of the 18 segments is gently adjusted by means of 6 actuators located behind it to ensure proper alignment – with the secondary mirror also having actuators that allow minute adjustments to be made to it, assisting the alignment process whilst ensuring the gathered light remains correctly focused on the non-moveable third mirror. It is not an easy process, the work is expected to run the full 120 days of the commissioning period.

2022 Space Highlights II

In the last instalment of Space Sunday, I mentioned some of the forthcoming missions planned for 2022. In addition to those I mentioned then (limited by space), here are some more – all of which I hope to cover in more detail as the year progresses.

• Axiom missions to ISS: Axiom Space plan to launch two “all private” missions to the International Space Station (ISS) utilising SpaceX Falcon 9 and Crew Dragon. Each mission will last around 8 days and focus on science and educational outreach. The first mission will launch at the end of February 2022, and the second in the autumn.
• Jupiter Icy moons Explorer (JUICE) mission: ESA’s mission to Jupiter, to primarily study three of its moons – Ganymede, Europa and Callisto – should launch in May 2022. Arriving in Jovian orbit in 2029, it will then create a 3-year study mission.
• Psyche asteroid mission: set for July 2002 and launched via a Falcon Heavy booster, NASA’s Psyche mission will study a metallic asteroid of the same name that orbits the Sun between Mars and Jupiter. It is believed the asteroid is the exposed nickel-iron core of an early planet. Thus, studies of it may offer new clues about how terrestrial planets like Earth form.
• India’s Gaganyaan space missions: India plans to complete an uncrewed launch of its new Gaganyaan crew vehicle in summer 2022, with a second test flight before the end of the year.

• ExoMars Rover launch: the long-awaited European Mars rover mission will launch between August and October, carrying the Rosalind Franklin rover to Mars. Once there it will join the ExoMars Trace Gas Orbiter (TGO), which arrived at Mars in 2016, to study the red planet.
• Dream Chaser ISS operations commence: Sierra Nevada Corporation’s Dream Chaser Cargo space plane will commence resupply flights to the ISS, carrying up to 5 tonnes of supplies and equipment to the station and returning around a tonne to Earth. The maiden Dream Chaser launch will mark the second flight of ULA’s new Vulcan rocket.
• Lunar missions:
  • US Nova-C lunar lander: the Intuitive Machines Nova-C land will launch atop a SpaceX Falcon 9 vehicle early in 2022, carrying five NASA Commercial Lunar Payload Services (CLPS) payloads to the Mare Serenitatis, including a UK-built lunar rover.
  • Russia: the Luna 25 robot mission to the Moon’s South Pole will launch in July, marking the first Russian mission to the Moon in 45 years, and the first to land in the lunar Polar Regions. It will carry nine instruments to research the lunar regolith and exosphere (atmosphere).

• • NASA lunar drilling mission: scheduled for launch in December 2022, the Polar Resources Ice Mining Experiment-1 (PRIME-1) is the first-ever mission designed to harvest water ice from inside the moon — a resource NASA hopes to utilize for its Artemis program.

In Brief

Biden White House Commits to ISS Extension

The Biden administration  has formally supported extending operations of the International Space Station through the end of the decade, an announcement that is neither surprising nor addresses how to get all of the station’s partners, notably Russia, to agree on the station’s future.

NASA has wanted to continue operating the ISS through until 2030 for several years, but has lacked outright political support to do so. In 2018, the US Senate agreed to extend US ISS operations through until 2028 or 2030, but the move failed to gain the required two-third House majority in order to pass. Support from the White House may help the agency gain full US support for the mission, and as a result of it, the European Space Agency has further indicated it would seek a resolution among members to continue to fund their side of station activities.

However, the major sticking point for operations lies with Russia. Most of the Russian modules on the station are growing increasingly old and subject to failure, and as such, Roscosmos is reluctant to continue supporting operations beyond 2024. In addition, geopolitics may impact the future of the ISS: Russia has already announced plans to operate its own space station at the expense of continued international cooperation with the ISS.

China Complete Key Station Robot Arm Test

On Thursday, January 6th, a large robotic arm on China’s space station successfully grasped and manoeuvred a cargo spacecraft in a crucial test ahead of upcoming module launches.

An artist’s impression of the robot arm test on the Chinese space station. Credit CMSAThe 10 metre long robotic arm on the Tianhe-1 module of China’s new Tiangong space station was used to grasp Tianzhou-2 supply vehicle that has been docked with the module since the end of May 2021, and move out away from the station, angling it through 20 degrees before returning it to the Tianhe-1’s forward docking port, where it reattached itself.

The 47-minute operation began at 22:12 UTC, as was designed to test the robot arm’s ability to manipulate and move large modules that will form a part of the station as it progresses. In particular, the test is vital to China’s plans to launch two science modules – called Wentian and Mengtian – to dock with Tianhe-1 in May / June and August / September 2022 respectively, thus completing the Tiangong space station.

Hubble Space Telescope’s One  Billion Seconds

One January 1st, 2022, the Hubble Space Telescope (HST) achieved another milestone in its distinguished career – notching up 1 billion seconds in orbit since its launch on April 24th, 1990. That’s 31.7 years of near-continuous operations in Earth’s orbit.

A joint NASA / ESA project, HST has contributed massively to our understanding of the solar system, our galaxy and the universe as a whole. Despite recent issues with the observatory, it is hoped that HST will continue to operate through the 2020s and well into the 2030s.

Following its launch on December 25th, the James Webb Space Telescope (JWST) has completed several major steps in the deploying its critical hardware as it continues its month-long voyage towards its operational orbit at the Earth-Sun L2 Lagrange point.
Here’s a brief summary of what has happened thus far with deployments.

In the early houses of Wednesday, December 29th (UTC), Earth, JWST unfolded the forward sunshield pallet, lowering it away from its stowed position in front of the central deployable tower supporting the (still folded) primary and secondary mirror assemblies and the telescope’s massive radiator, and containing JWST’s vital electronics and science instruments.

The lowering process took 20 minutes to complete, and was followed by the aft sunshield pallet being unfolded from behind the mirror tower in an 18-minute operation. After this, JWST went through several hours of additional operations, including ensuring the pallets were correctly in place and their sub-systems operational, and orienting the observatory with respect to the Sun to provide optimal shielding when the sunshield is deployed and tensioned. Once all this was completed, the command was given for the pallets to lock themselves in their deployed condition.

Later on the 29th, the deployable tower was raised some 1.2 metres from its “stowed” state over a 6-hour period. This moved it away from JWST’s thrusters and provided the room needed for the sunshields to be deployed and tensioned.

Thursday, December 30th saw the deployment of the sunshield commence. A three-part process, and one vital to the observatory’s operations, this started with the drawing back of the membranes that have protected the delicate sunshield.

On December 31st, the booms that extend the five layers of the sunshield were extended. Operations began at 18:30 UTC, with the five segments of the portside boom extending outwards from the mid-point between the two sunshield pallets. The procedure took just over three hours to complete, and was followed by the extension of the starboard boom, which took a similar amount of time, also drawing out the membranes of the sunshield on that side of the telescope.

Overall, the deployment of both booms took longer than anticipated, but was successfully completed, with operations then being halted for New Years Day. On January 2nd, operations resumed on the tensioning of the membranes. A 2-day operation, this involves separating each of the 5 membranes from the others and then tensioning it using the side booms and four fore-and-aft boom mechanisms. Once this has been completed, the focus will switch to deploying the telescope’s “eyes” – its secondary and primary mirrors.

The other news on the programme is that such was the accuracy with which the Ariane 5 placed JWST onto its transfer orbit, coupled with the smoothness of the first “mid-course” thruster burns, far less propellants that had been estimated. This now means that the observatory has sufficient reserves to complete at least a 10-year mission (although NASA remains focused on the 5-year primary mission).

Space Highlights for 2022

I generally try to look ahead to key space events at the start of the year, and while this may not be as comprehensive as previous years, but the following is offered as a broad summary of high points.

Launches

Several new launch vehicles will undergo initial launch tests / flight in 2022, including:

• Block 1 NASA Space Launch System (USA): maiden flight, February 2022 carrying the Artemis 1 mission hardware and cubesats for ten missions in the CubeSat Launch Initiative (CSLI), and three missions in the Cube Quest Challenge. The payloads will be sent on a trans-lunar injection trajectory.

Continue reading “Space Sunday: JWST and 2022 highlights” →

The world’s largest and most powerful space telescope yet built – the James Webb Space Telescope (JWST) – finally made its way into space on Christmas Day, December 25th, 2021, marking the start of a mission almost 30 years in the making.

That mission is multi-part in its scope, encompassing as it does looking back to the origins of the universe and the galaxies around us, together with gaining a greater understanding of the nature and formation of galaxies, stars and planetary systems, and learning more about the nature of worlds beyond our own solar system, as well as seeking signs of the potential origins of life. It is a mission that has been plagued by technical and other issues that have repeatedly delayed its launch – and high winds along its path of ascent to orbit caused one final delay, pushing the launch back from Christmas Eve to Christmas day.

Final countdown commenced several hours ahead of lift-off, with the Ariane 5 launch vehicle igniting its engines as scheduled at 12:20 UTC, rising into the sky over the European Spaceport near Kourou, French Guiana, carrying the US $10 billion telescope on the first leg of a journey to its operational destination that will take it almost a month to complete. Along the way it will go through a series of complex activities along the way, each one vital to its operational success.

The first three of these activities came just half-an-hour after lift-off, with the separation of the telescope from its Ariane upper stage after the latter had boosted it onto the start of its 1.6 million kilometre journey away from Earth. Almost at the same time, JWST deployed the solar array vital for supplying it with electrical power. This was followed two hours later by the deployment of the high gain communications antenna and, 12 hours after launch, JWST completed the first “mid-course” correction to its trajectory, steering itself more closely towards its final destination.

This destination lies close to the Earth- Sun L2 Lagrange point, 1.6 million km further out from the Sun than Earth’s orbit, but which orbits the Sun in the same period of time as Earth. It’s a location selected for JWST’s operations for a number of reasons, including:

• It effectively puts the Earth, Moon and Sun “behind” the telescope, affording it uninterrupted views of the solar system and all that lies beyond it.
• It is a semi-stable position in space that orbits the Sun at the same time as Earth. This both allows for continuous direct-line communications, and reduces the amount of propellants JWST would otherwise require for basic operations such as station-keeping and orbital corrections.

Even so, operations at the position will not be straightforward. As the L2 position is a point of gravitational equilibrium, JWST will operate in an orbit 800,000 km wide around it. Whilst relatively stable, this orbit will require JWST to make small periodic adjustments every 23 or so days. Given it can only carry a finite amount of propellants (168 kg) for these adjustments, the telescope effectively has an operational “shelf life”: it’s primary mission is set at just 5 years – although it is hoped it has sufficient propellants for at least 10 years worth of controlled observations.

Having been launched in a “packed” form that allowed it to fit inside the payload fairing of its launch vehicle, JWST will spend the next two weeks gradually “unfolding” itself, as per the video below, with a number of firings of its thrusters to fine-tune its flight to its intended orbit.

All of these activities are vital to JWST being able to perform its desired mission, but perhaps the two most important are the deployment of the telescope’s secondary and primary mirrors, and that of its incredible and delicate heat shield.

The optics deployment will see the booms supporting the secondary mirror that reflects light gathered from the primary back to where it can be delivered by a third mirror to the instruments deep inside JWST. The second part comes with the unfolding of the “table flap” elements of the primary mirror, allowing it to reach its full 6.5 metre diameter, almost 2.5 times the diameter of the primary mirror on the Hubble Space Telescope. (HST), and with potentially 100 times its power.

JWST is primarily intended to operate in the infrared, but in order to do so, its instruments and science systems must be kept very cold. If any of them exceed 50ºK (-223.2ºC), the heat they generate will be registered in the infrared; potentially overwhelming the telescope’s ability to capture the infrared light of stellar objects. Given that JWST will be in permanent sunlight, maintaining such an incredibly low temperature this is a considerable challenge – hence the vital role of JWST’s remarkable heat shield.

This comprises 5 layers of Kapton E polymide formed into sheets as thin as a human hair and then covered on both sides with a thin membrane of aluminium, this shield is carried folded within two “pallets” that also need to be unfolded to form the “base” of the telescope.

Once these pallets have unfolded, booms can be extended on either side of JWST, allowing the 5 layers of the heat shield to be unfurled like the sails of a ship, and then tensioned off. This will provide an area of shadow the size of a tennis court within which the instruments and optics of the telescope will sit, while radiators behind the main mirror will circulate the heat absorbed by the shield and radiate it back into the cold shadow without impacting telescope operations.

Continue reading “Space Sunday: JWST and a touch of SpaceX” →