NASA working on nuclear rocket for manned Mars trips

Should result in 'nauts receiving less radiation


Since being redirected away from Bush-era plans for a base on the Moon towards a manned Mars mission, NASA has realigned its nuclear-tech-in-space efforts away from a Moonbase powerplant and towards an atomic-powered rocket able to get astronauts to the red planet quickly, without receiving dangerous exposure to cosmic radiation.

Concept dated 1960 of a nuclear-thermal ship in orbit above Mars. Credit: NASA

What? It's the year 2011 and you're still mucking about with lousy chemical rockets?

Most plans for a Mars mission assume a ship propelled by ordinary chemical rockets of the type used in all manned missions so far. These get through fuel very rapidly and can only throw it out of their exhausts at a limited rate, putting a strict cap on the speed a Mars ship can achieve if it is to slow down again at its destination and then return. Thus it's generally assumed – as in a recent simulated voyage – that the journey out and back would involve spending a year or more in space.

The big problem with this, one that has yet to really be addressed, is that space is full of dangerous radiation. Normal background cosmic rays are bad enough over a long period: furthermore over a lengthy voyage it's almost certain that there would be one or more major solar storms which could easily take astronauts over their permitted safe dose limits for the entire journey in a matter of days. Sufficient shielding to make a spaceship safe would be so heavy that the craft could probably never be lifted off Earth at reasonable cost.

The only people who have ever been subject to these hazards were the Apollo moon astronauts of yesteryear, and their journeys beyond the protective magnetic fields of Earth were only days long. Even then an inopportune solar event during an Apollo mission could have had disastrous consequences.

For all these reasons, it would be a good idea if more powerful propulsion than chemical rockets could be used for the trip, so cutting down journey time and hazard to the crew. This could also mean less need for supplies, improving the feasibility of the whole plan.

Since nobody has yet come up with any way to provide a thrust in space without throwing reaction mass out of the back of the ship, these various more advanced concepts are still rockets: but they use different means of hurling the mass.

One such concept is to heat the fuel up not by burning it with oxidiser, but using a nuclear reactor. This can potentially make it a lot hotter than mere burning, so expelling it from the exhaust faster and getting more poke out of a given amount of fuel. It was formerly assumed that such rockets would actually become the standard means not of interplanetary travel, but also of normal space launch: the visionaries of the 1940s, if they could have looked ahead to today, would have been dumfounded to find humanity still reliant on feeble chemical propellants (so lame that they have to be used in throwaway multi-stage stacks to achieve orbit) in the year 2011.

The nuclear-safety principle of As Low As Reasonably Achievable on emissions put paid to the idea of using nuclear rockets in atmosphere, though NASA was still working on them as late as 1973 – funnily enough with the idea of using them on manned Mars missions. But the NERVA programme fell victim to the post-Apollo NASA budget cuts, and since then very little work has been done on nuclear rockets as such.

However, under President Bush's Constellation plans, NASA was directed to return to the Moon – and perhaps to establish a permanently manned base there. Such a base would need power, and unless it could be built in a permanently-sunlit spot atop a towering crater rim at one of the lunar poles, solar power would not be an option as most of the Moon is subject to extremely cold two-week-long nights.

Thus, boffins at NASA's Marshall Space Flight Center began work on a small nuclear reactor that could be shipped to the Moon. That plan lost its purpose when President Obama, having found that Congress wouldn't authorise enough cash to pay for the Constellation moon plans, scrapped the idea and laid out vague aspirations for manned deep-space missions to other destinations – including Mars.

Similar topics


Other stories you might like

  • NASA ignores InSight's battery woes in pursuit of data
    Space boffins: Nevermind ekeing out the battery, let it go out in a blaze of glory!

    Pondering what services to switch off to keep your laptop going just that bit longer? NASA engineers can relate, having decided the Mars InSight lander will go out on a high: they plan to burn through the remaining power to keep the science flowing until the bitter end.

    The InSight lander is in a precarious position regarding power. A build-up of dust has meant the spacecraft's solar panels are no longer generating anywhere near enough power to keep the batteries charged. The result is an automatic shutdown of the payload, although there is a chance InSight might still be able to keep communicating until the end of the year.

    Almost all of InSight's instruments have already been powered down, but the seismometer remains active and able to detect seismic activity on Mars (such as Marsquakes.) The seismometer was expected to be active until the end of June, at which point it too would be shut-down in order to eke out the lander's dwindling supply of power just a little longer.

    Continue reading
  • NASA circles August in its diary to put Artemis I capsule in Moon orbit
    First steps by humans to recapture planet's natural satellite

    NASA is finally ready to launch its unmanned Orion spacecraft and put it in the orbit of the Moon. Lift-off from Earth is now expected in late August using a Space Launch System (SLS) rocket.

    This launch, a mission dubbed Artemis I, will be a vital stage in the Artemis series, which has the long-term goal of ferrying humans to the lunar surface using Orion capsules and SLS technology.

    Earlier this week NASA held a wet dress rehearsal (WDR) for the SLS vehicle – fueling it and getting within 10 seconds of launch. The test uncovered 13 problems, including a hydrogen fuel leak in the main booster, though NASA has declared that everything's fine for a launch next month.

    Continue reading
  • Mars Express orbiter to get code update after 19 years
    And over millions of miles, too. Piece of cake!?

    The software on ESA's Mars Express spacecraft is to be upgraded after nearly two decades, giving the orbiter capabilities to hunt for water beneath the planet and study its larger moon, Phobos.

    Mars Express was launched on June 2, 2003, and was initially made up of two components: the Mars Express Orbiter and the Beagle 2 lander. Unfortunately, the lander failed to make contact with Earth after it was released and arrived at the surface of the Red Planet. It is presumed lost. The orbiter, however, is still working after 19 years in service, spinning around Mars.

    Now, engineers at the Istituto Nazionale di Astrofisica (INAF), Italy, are revamping the spacecraft's software. The upgrade will allow the Mars Express Orbiter to continue searching for water locked beneath the Martian surface using its MARSIS radio-wave instrument and monitor the planet's closest satellite, Phobos, more efficiently. MARSIS is today operated by INAF and funded by the Italian Space Agency.

    Continue reading
  • NASA's mini-spacecraft CAPSTONE just launched on its journey to the Moon
    25kg CubeSat the size of a bar fridge will plot course for Gateway space station, pave way for human boots on Moon

    Rocket Lab has sent NASA's Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) spacecraft on its way to the Moon atop an Electron rocket launched from New Zealand.

    The launch had been subject to a number of delays, but at 09.55 UTC today, the Electron lifted off from Rocket Lab's Launch Complex 1 on the Mahia Peninsula of New Zealand.

    Continue reading
  • Whatever hit the Moon in March, it left this weird double crater
    NASA probe reveals strange hole created by suspected Chinese junk

    Pic When space junk crashed into the Moon earlier this year, it made not one but two craters on the lunar surface, judging from images revealed by NASA on Friday.

    Astronomers predicted a mysterious object would hit the Moon on March 4 after tracking the debris for months. The object was large, and believed to be a spent rocket booster from the Chinese National Space Administration's Long March 3C vehicle that launched the Chang'e 5-T1 spacecraft in 2014.

    The details are fuzzy. Space agencies tend to monitor junk closer to home, and don't really keep an eye on what might be littering other planetary objects. It was difficult to confirm the nature of the crash; experts reckoned it would probably leave behind a crater. Now, NASA's Lunar Reconnaissance Orbiter (LRO) has spied telltale signs of an impact at the surface. Pictures taken by the probe reveal an odd hole shaped like a peanut shell on the surface of the Moon, presumably caused by the Chinese junk.

    Continue reading
  • NASA tricks Artemis launch computer by masking data showing a leak
    Plus it aborts ISS reboost. Not the greatest start to the week, was it?

    NASA engineers had to work fast to avoid another leak affecting the latest Artemis dry run, just hours after an attempt to reboost the International Space Station (ISS) via the Cygnus freighter was aborted following a few short seconds.

    The US space agency on Monday rolled the huge Artemis I stack back to its Florida launchpad having worked through the leaks and problems that had beset its previous attempt at fueling the beast in April for an earlier dress rehearsal of the final countdown.

    As propellant was loaded into the rocket, controllers noted a hydrogen leak in the quick-disconnect that attaches an umbilical from the tail service mast on the mobile launcher to the core stage of the rocket.

    Continue reading
  • NASA's InSight doomed as Mars dust coats solar panels
    The little lander that couldn't (any longer)

    The Martian InSight lander will no longer be able to function within months as dust continues to pile up on its solar panels, starving it of energy, NASA reported on Tuesday.

    Launched from Earth in 2018, the six-metre-wide machine's mission was sent to study the Red Planet below its surface. InSight is armed with a range of instruments, including a robotic arm, seismometer, and a soil temperature sensor. Astronomers figured the data would help them understand how the rocky cores of planets in the Solar System formed and evolved over time.

    "InSight has transformed our understanding of the interiors of rocky planets and set the stage for future missions," Lori Glaze, director of NASA's Planetary Science Division, said in a statement. "We can apply what we've learned about Mars' inner structure to Earth, the Moon, Venus, and even rocky planets in other solar systems."

    Continue reading

Biting the hand that feeds IT © 1998–2022