A planned flagship spacecraft to Uranus was aiming to use Jupiter for a gravitational boost to shorten its journey to the outer solar system. Now that the mission’s launch date has been pushed back, it’ll need to find another way to its target.

Redesigning the Route

Uranus and Neptune, the ice giants of our solar system, have been comparatively neglected by humanity’s fleet of interplanetary probes. While all of the other major bodies have been visited by at least an orbiter or even a lander, the most detailed exploration we’ve done of these two planets happened when the Voyager 2 spacecraft went screaming past on its way toward interstellar space.

So it was no surprise when a panel of scientists and engineers charged with setting scientific exploration priorities between 2023 and 2032 recommended finally sending a spacecraft to Uranus, depositing it into orbit around the planet, and keeping it there for a while to collect data. The study itself suggested a basic design for the mission: a pair of spacecraft, one orbiter and one sacrificial atmospheric probe, collectively weighing about 4,000 kg.

Getting these spacecraft to their destination will be a challenge The thriftiest path to get to Uranus, a trajectory called a Hohmann transfer that’s been used for other missions aimed elsewhere in the solar system, would take 16–17 years. Rather than accept the long wait, the original authors suggested that the mission instead fly toward Jupiter, using the giant planet’s massive gravitational tug to slingshot the spacecraft toward Uranus.

However, this plan relied on Jupiter being in just the right place when the spacecraft approached. This in turn relied on the mission launching sometime in 2031 or 2032: any earlier or later, the slingshot would be aimed in the wrong direction. Now that timelines and budgets have slipped for this flagship mission, hitting this launch window seems unlikely. And, without the boost from Jupiter, the mission will have to cross 20 au of open interplanetary space on its own.

Solar Electric Propulsion to the Rescue

Recently, a team led by Amy Simon, NASA Goddard Space Flight Center, took on this challenge and tried to chart a new path through the solar system. The team realized that solar electric propulsion (SEP), a technique that relies on using solar panels to create electricity and accelerate ions to create thrust, might offer a path forward. By using SEP, the mission could leave Earth, unfurl wings of solar panels, then gradually accelerate for as long as there was enough sunlight to power the engine.

The power levels would likely get too low just a few astronomical units into their journey, but that would be enough: after discarding the SEP stage, the mission could coast to Uranus on a journey that would take only 13 years. Even better, this technology has a proven flight history and would require little maturation or development. The BepiColombo mission to Mercury is currently using SEP, and similar techniques are used on satellites in Earth orbit today.

Simon and collaborators also took on a number of other challenges that have cropped up since the mission was proposed, including fewer available plutonium power sources and a re-assessment of Uranus’s rings that revealed hazards in the original flight path. Their work brings the mission closer to the launch pad and illustrates how much iteration goes into the spacecraft that finally takes to the stars.

Citation

“Uranus Orbiter and Probe: Mission Challenges and Concept Updates Since the Origins, Worlds, and Life Decadal Survey,” Amy A. Simon et al 2026 Planet Sci. J. 7 143. doi:10.3847/PSJ/ae680c

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The UK’s Science and Technology Facilities Council (STFC) recently announced funding cuts to a range of physics and astronomy projects as it seeks to reduce costs. One of the most high-profile casualties is e-MERLIN, a network of seven radio telescopes spread across the UK, including the iconic Lovell Telescope at Jodrell Bank.

To discover what the cuts could mean for UK science and the livelihoods of those affected, podcast host Andrew Glester caught up with two astronomers at Jodrell Bank: Simon Garrington, e-MERLIN director, and David Williams-Baldwin, an e-MERLIN research support scientist.

They discuss why the cuts have caused such alarm among scientists, how the UK astronomy community is mobilizing in opposition, and why the consequences could extend far beyond Jodrell Bank.

e-MERLIN combines signals from its telescopes to produce sharp radio images of the Universe – with a resolution comparable to that of the Hubble Space Telescope. As things stand, funding for the telescope array will run out in March 2028, putting the future of the network and scientific operations at Jodrell Bank in doubt.

It’s an uncertain time for an observatory that was granted UNESCO World Heritage status in July 2019 for its historical contributions and its technical and scientific ingenuity since the 1940s.

An STFC spokesperson emphasises that Jodrell Bank is “not closing” and “will continue to play an important role in UK science”. This includes the Square Kilometre Array Observatory that has its headquarters at Jodrell Bank as well as other radio astronomy research projects in the UK and elsewhere.

“We recognise the strength of feeling about Jodrell Bank and the e-MERLIN network, and the contribution they have made to UK science. The achievements of the scientists, engineers and staff who have supported e-MERLIN over many years are widely respected across the research community,” they add. “We are focusing on the next generation of radio astronomy to ensure UK researchers continue to be at the forefront of the field. Rising cost pressures mean that we have had to make difficult choices about STFC funding to make sure we are able to fund world class research sustainably into the future.”

The post With e-MERLIN facing the axe, what next for Jodrell Bank and UK astronomy? appeared first on Physics World.

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A radiation shielding vest tested during the uncrewed Artemis I flight in 2022 has been shown to significantly reduce the radiation dose that future astronauts or deep-space tourists might receive.

The data for this analysis were obtained via seating two human-tissue-equivalent female torso phantoms in the Orion crew capsule. While the “Zohar” phantom wore the new AstroRad vest, its travel companion “Helga” did not. Numerous radiation dosimeters placed in and on the phantoms allowed the received radiation dose to be compared.

“Exposure to radiation in space is unavoidable, and a single major solar particle event (SPE) can deliver more than one-third of NASA’s 600 millisievert career effective-dose limit. A three-year round trip to Mars would equal or exceed the career limit, which corresponds to a 3% mortality risk from radiation-induced cancer. So we developed the AstroRad vest to significantly reduce this hazard,” explains immunologist Oren Milstein, CEO of StemRad Radiation Protection, which began developing the vest with Lockheed Martin in 2015.

The shielding thickness varies throughout the garment according to the radiation sensitivity of the underlying organs, with breasts, colon, lungs, ovaries, stomach and red bone marrow having concentrated shielding in the test vest. Milstein was inspired to develop this targeted architecture based on the experiences of his PhD supervisor, who treated the first responders to the 1986 Chernobyl nuclear power plant disaster.

With damage to bone marrow the accepted cause of death for all those emergency workers who lost their lives within months of the accident, “that heritage instilled in me a desire to protect people from radiation by selective shielding of the bone marrow,” Milstein explains, adding that the female focus of this experiment is because women have a higher predicted risk of radiation-induced cancer than men.

Astronauts currently shield from SPEs in “storm shelters” consisting of barricades of supplies, or by moving into areas containing more hardware against the walls. AstroRad provides a similar level of protection to the most robust shelter configuration while also “allowing the astronaut wearing it to move around the cabin and continue mission-critical tasks,” radiation physicist Jordan Houri, lead scientist for space exploration at StemRad, tells Physics World.

To maintain flexibility, the vest is constructed from thousands of hexagonal tessellated rods of high-density polyethylene (HDPE) sandwiched between two layers of elastic fabric. The shielding components can also slide past one another and stretch. HDPE was chosen for its high proportion of hydrogen – which is extremely effective at shielding against charged particle space radiation.

While Artemis I did not encounter a solar storm, Orion traversed the inner Van Allen belt, whose protons cover a similar energy range to those in SPEs. This enabled the team to construct a Monte Carlo model of the experiment for testing different radiation environments.

“We created digital twins of Helga and Zohar, the AstroRad vest, radiation detectors and spacecraft shielding,” explains Houri. “Using this model, we generated hundreds of billions of virtual protons and electrons representing the radiation environment of the inner Van Allen belt, before comparing the predicted detector responses directly with the measurements recorded during Artemis I.”

With close agreement found, the researchers then simulated measured SPEs from August 1972 and October 1989. As detailed in their recent Science Advances paper, this revealed that wearing AstroRad would reduce effective dose by around 60% in an August 1972-type scenario, and by almost 40% for a 1989-type SPE – sparing astronauts the dose equivalent from up to 193 and 131 days of deep space travel, respectively.

Combining these results with those from previous experiments, which tested the vests’ ergonomics on the International Space Station, is allowing the researchers to improve comfort and ease of motion, and reduce mass. They are also exploring whether lighter, empty vests could be filled with recycled polyethylene after launch.

Alongside the health benefits, reducing radiation exposure makes economic sense as it extends astronauts’ careers, concludes Milstein, who hopes that the AstroRad vests can help “make lunar habitation and Mars travel truly sustainable and not just a dream”.

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