The US National Aeronautics and Space Administration (NASA) announced on 13 August that it had selected two proposals for a US$75 million mission to help scientists better understand the “fundamental nature of space and how it changes in response to planetary atmospheres, radiation from the Sun, and interstellar particles”.

Each of the proposals will receive US$400,000 in funding to conduct a nine-month long mission concept study as part of NASA’s heliophysics program aka the Heliophysics Science Mission of Opportunity.

Following the completion of these studies, NASA will choose one of the proposals to launch as a secondary payload on the agency’s Interstellar Mapping and Acceleration Probe (IMAP). According to NASA, the proposals were selected based on “potential science value and feasibility of development plans” and the whole mission is funded by NASA’s Solar Terrestrial Probes program.

IMAP currently is scheduled to launch in October 2024 to orbit a point between Earth and the Sun known as the first Lagrangian point (L1). From there, researchers expect it will help them to “better understand the interstellar boundary region, where particles from the Sun collide with material from the rest of the galaxy”.

This distant area controls the amount of harmful cosmic radiation entering the heliosphere, the magnetic bubble that shields the solar system from charged particles that surround it. Cosmic rays from the galaxy and beyond affect astronauts and can harm technological systems, and may play a role in the presence of life in the universe.

Under the Spatial/Spectral Imaging of Heliospheric Lyman Alpha (SIHLA) proposal, scientists want to map the entire sky to determine the shape and underlying mechanisms of the boundary between the heliosphere, the area of our Sun’s magnetic influence, and the interstellar medium, a boundary known as the heliopause.

The observations would gather far-ultraviolet light emitted from hydrogen atoms, which is key for examining many astrophysical phenomena, including planetary atmospheres and comets, because a large part of the universe is composed of hydrogen.

SIHLA will focus on mapping the velocity and distribution of the solar wind – the outpouring of particles from the Sun – helping to develop scientists’ understanding of what drives structure in the solar wind and heliopause.

The Global Lyman-alpha Imagers of the Dynamic Exosphere (GLIDE) mission would study variability in Earth’s exosphere – the uppermost region of its atmosphere – by tracking far ultraviolet light emitted from hydrogen.

The proposed mission would fill an existing measurement gap, as only a handful of such images previously have been made from outside the exosphere, NASA said. The mission would “gather observations at a high rate, with a view of the entire exosphere, ensuring a truly global and comprehensive set of data”.

Understanding the ways in which Earth’s exosphere changes in response to influences of the Sun above or the atmosphere below, would give scientists “better ways” to forecast and mitigate the ways in which space weather can interfere with radio communications in space.

“Launching missions together like this is a great way to ensure maximum science return while keeping costs low,” Peg Luce, deputy director of NASA’s Heliophysics Division, said in a statement.

“We carefully select new heliophysics spacecraft to complement the well-placed spacecraft NASA has in orbit to study this vast solar wind system – and our rideshare initiative increases our opportunities to send such key missions into space,” she added.

Engineers at the US National Aeronautics and Space Administration (NASA) have successfully tested the system that will deploy the secondary mirror of the James Webb Space Telescope (JWST), the agency said on 6 August.

The James Webb Space Telescope is a large, space-based observatory, optimized for infrared wavelengths, which will complement and extend the discoveries of the Hubble Space Telescope. It is expected to launch in 2021.

NASA intends for the telescope to cover longer wavelengths of light than Hubble and to have greatly improved sensitivity. The longer wavelengths should let it “look further back in time to see the first galaxies that formed in the early universe, and to peer inside dust clouds where stars and planetary systems are forming today”.

Before it can do any of these things, the telescope must “perform an extremely choreographed series of deployments, extensions and movements” to “bring the observatory to life” shortly after launch. In its fully deployed form, the telescope is too big to fit in any rocket available so it has been “engineered to intricately fold in on itself to achieve a much smaller size during transport”.

Technicians and engineers recently tested commanding the JWST to deploy the support structure that holds its secondary mirror in place. NASA sees this as is a critical milestone in preparing the observatory for its journey to orbit.

“The proper deployment and positioning of [the JWST’s] secondary mirror is what makes this a telescope – without it, Webb would not be able to perform the revolutionary science we expect it to achieve,” Lee Feinberg, optical telescope element manager for the JWST at NASA’s Goddard Space Flight Centre in Maryland, said in a statement that included a time-lapse video of the test.

“This successful deployment test is another significant step towards completing the final observatory,” he added.

It also demonstrated that the electronic connection between the spacecraft and the telescope is working properly, and is capable of delivering commands throughout the observatory as designed.

The secondary mirror is one of the most important pieces of equipment on the telescope, and is essential to the success of the mission. When deployed, this mirror will sit out in front of the JWST’s hexagonal primary mirrors, which form an iconic honeycomb-like shape.

This smaller circular mirror serves an important role in collecting light from the telescope’s 18 primary mirrors into a focused beam. That beam is then sent down into the tertiary and fine steering mirrors, and finally to its four powerful scientific instruments.

The project’s next significant milestone will be the mating of the two halves of the telescope, which are being built separately. The construction of the telescope has been marred by delays and cost overruns that have pushed the launch date from 2018 to 2021.

The JWST is named after James E. Webb, NASA’s second administrator. Webb is best known for leading Apollo, a series of lunar exploration programs that landed the first humans on the Moon. He also initiated a vigorous space science program that was responsible for over 75 launches during his tenure, including America’s first interplanetary explorers.

The US National Aeronautics and Space Administration (NASA) is developing mirrors that could double the sensitivity of X-ray telescopes, the agency said on 29 July.

Imaging systems based on x-rays use mirrors to reflect x-rays off an object at incidental angles, in the same way that more traditional optics or imaging systems reflect light off objects so that they can be viewed with naked eye or photographed. They are typically made of glass, ceramic, or metal foil, coated by a reflective layer – the most commonly used materials are gold and iridium.

Recent testing has shown that super-thin, lightweight X-ray mirrors made of a material commonly used to make computer chips can meet the stringent imaging requirements of next-generation X-ray observatories.

They are fifty times lighter – a two orders-of-magnitude leap in sensitivity – than those currently fitted in NASA’s flagship Chandra X-ray observatory and the European Space Agency’s Advanced Telescope for High-Energy Astrophysics, or Athena.

The mirrors could be fitted into the conceptual Lynx X-ray Observatory which is expected to launch at some point in the 2030s – one of four potential missions that scientists vetted as worthy pursuits under the 2020 Decadal Survey for Astrophysics.

If selected and ultimately launched in the 2030s, Lynx could potentially carry tens of thousands of the mirror segments. Chandra itself offered a significant leap in capability when it launched in 1999. It can observe X-ray sources — exploded stars, clusters of galaxies, and matter around black holes —100 times fainter than those observed by previous X-ray telescopes.

The mirrors in question are being developed by Will Zhang and his team at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Zhang and his team have secured a nearer-term flight opportunity than Lynx, aboard a sounding rocket mission scheduled for 2021, which would represent the new technology’s first demonstration in space.

Seven years in the making

Efforts to develop the new mirrors began seven years ago when Zhang started to experiment with mono-crystalline, a single-crystal silicon that had not previously been used to create x-ray mirrors.

His goal — given the cost of building space observatories, which only increase in price as they get larger and heavier — was to develop easily reproducible, lightweight, super-thin mirrors, without sacrificing quality.

“What we’ve done is shown from a scientific perspective and empirically that these optics can be built using an inexpensive, abundantly available material that is immune from the internal stresses that can change the shape of X-ray mirrors made of glass, the more traditional mirror-making material”, Zhang said in a statement.

According to a NASA-commissioned panel of 40 experts, Zhang’s mirrors made from the brittle, highly stable silicon are capable of producing the same image quality as the four larger – and heavier – pairs currently flying on Chandra. The panel also deemed two other technologies – full-shell mirrors and adjustable optics – as able to fulfil the requirements of the conceptual Lynx Observatory.

Not only could Zhang’s mirrors provide an image resolution comparable to the quality of an ultra-high-definition television screen, they also met his low-mass requirements. But, Zhang said, he and his team are still “far, far away from flying our optics”.

Next steps

Zhang and his team now have to figure out how to bond these fragile mirror segments inside the canister that protects the entire mirror assembly during a rocket launch and maintains their “nested alignment”.

“We have a lot to do, and not a lot of time to do it,” Zhang said. “This is now an engineering challenge.”

He added that “time is of the essence” because in two years, he and his team are expected to deliver a 288-segment mirror assembly to Randall McEntaffer, a professor at Pennsylvania State University in State College who is developing a sounding rocket mission called the Off-plane Grating Rocket Experiment (OGRE), expected to launch from the Wallops Flight Facility in 2021.

In addition to the mirrors, OGRE will carry a “university-developed spectrograph equipped with next-generation X-ray diffraction gratings used to split X-ray light into its component colours or wavelengths to reveal an object’s temperature, chemical makeup, and other physical properties”.

Zhang expects that OGGRE will “do much to advance the mirror assembly” and that the mission will help to determine if its design will be able to protect the delicate mirrors from the extreme launch forces during lift-off and ascent through the Earth’s atmosphere.

Even if Lynx isn’t chosen for development by the 2020 Decadal Survey, Zhang envisions a bright future for the team’s optics. Other proposed missions could benefit, he said, including a couple X-ray observatories now being investigated as potential astrophysics Probe-class missions and another now being considered by the Japanese.

“Five years ago, people said it couldn’t be done, but we proved our ideas,” Zhang said. “My team is grateful to Goddard’s Internal Research and Development program for giving us the seed money. We couldn’t have achieved this without it.