5 Challenges Facing U.S. Space Exploration

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The U.S. space program is at a crossroads. With a new presidential administration, the country’s future in space is uncertain. There have been hints that the new regime may direct NASA to “explore space, not Earth.” That is troubling — as the new administration attempts to erase all efforts toward climate change studies — yet it may present a hidden opportunity for NASA to ask for, say, big-budget Mars missions. The good news: NASA’s fiscal year 2016 budget of $19.3 billion increased more than $1.2 billion, its largest increase since 2008. And that funding level has been maintained for 2017. The bad news: such increases can take years or even decades to reach the launch pad, as hard decisions made during budgetary lean years will resonate for some time to come. Here are a few troubling issues that loom on NASA’s horizon.


5. U.S. Relies on Russia to Launch Astronauts

The 2011 launch of Space Shuttle Atlantis on mission STS-135, the last crewed space mission launched in the U.S. © Bill Ingalls

It seems hard to believe, but the nation that sent astronauts to the Moon and back almost routinely a half-century ago currently cannot launch a man into space. And although the first flights with astronauts aboard the SpaceX Dragon capsule might occur in May 2018, NASA’s first crewed SLS flights aren’t expected until 2021. Among the big three players in space (the U.S., Russia and China) the United States alone does not have the current capability to launch astronauts from its own soil. While U.S. astronauts still travel to the International Space Station, they now rely on the Russians to get there via Soyuz. Given the strained relations between the two countries at the moment, some see that reliance as a potential problem.

It’s ironic that while the Russians operate with a much smaller budget than NASA, they have never had a gap in their crewed spaceflight program. NASA has had two lengthy breaks. The first lasted from the end of the Apollo program in 1975 to the first shuttle flight in 1980. The current gap will soon be even longer, dating to the end of the shuttle program in July 2011.


4. Fuel Shortage Delaying Future Missions to Outer Planets

Future missions to the outer planets, similar to the New Horizons spacecraft that visited Pluto in 2015, are threatened by a lack of fuel. Credit: NASA

NASA has sent nine missions to the outer planets, dating back to Pioneer 10’s flyby of Jupiter in 1973. NASA is the only space agency that has ventured beyond the asteroid belt to date, although the European Space Agency’s Huygens lander did hitch a ride to Saturn’s large moon Titan on NASA’s Cassini spacecraft. But soon, NASA’s long-running presence among the outer planets will end. Cassini finishes its mission to Saturn this year. Juno completes its Jupiter encounter next year, and New Horizons heads into the outer solar system after flying past a Kuiper Belt object on New Year’s Day, 2019. All of these missions wrap up in the next few years, with no replacements for perhaps a decade.

One culprit: the ongoing shortage of Plutonium-238 to power deep-space probes. A byproduct of nuclear weapons production during the Cold War, the U.S. stopped producing Pu-238 in 1988 and only recently restarted small-scale production for NASA in 2013. Yet it’s expensive and time-consuming to make, and it will be several years before NASA rebuilds its stockpile of fuel. Unfortunately, the fissile Pu-239 isotope used in nuclear bombs can’t be re-purposed. Plutonium is the only known compact power source for outer solar system exploration. Although Juno is the first spacecraft to explore Jupiter without plutonium, it requires three massive school bus-sized solar panels to do it. NASA also axed a program to design new Stirling nuclear generators that would have been four times as efficient in 2013, opting instead to continue using traditional radioisotope thermoelectric generators (RTGs).


3. NASA Picking Low-Cost Missions Instead of Ambitious Projects

NASA’s Psyche spacecraft is scheduled for launch in 2023. Credit: SSL/ASU/P. Rubin/NASA/JPL-Caltech

NASA recently selected two new asteroid missions for the 2020s: one will visit the metal asteroid 16 Psyche, and another will explore the Trojan asteroids in Jupiter’s orbit. That’s great, but many fear NASA is playing a budget shell game, selecting cheap, low-cost missions that are less attractive targets for cancellation. True, the idea that the current president could arbitrarily shut down NASA with a 4 a.m. tweet may be far-fetched. There’s always a tug of war between NASA’s robotic and human spaceflight program, and many fear that the space agency will circle the financial wagons around huge money pit programs such as the James Webb Space Telescope and the International Space Station at the expense of all other missions, as has happened in the past.

When it comes to planetary exploration, NASA selects three types of missions: relatively inexpensive Discovery-class missions, such as Dawn and MESSENGER, mid-range New Frontiers missions (examples include Juno and New Horizons), and large Flagship missions (Cassini). The two new asteroid missions are small Discovery-class missions costing less than $450 million each, and seem to be the future of space exploration. Long gone are the days when NASA could dream big (think JFK’s “Man on the Moon” speech) and get the budget to make it happen.


2. There is No Replacement for the ISS

Expedition 38 astronauts aboard the International Space Station in 2014. The station’s lifespan is nearing its end. Credit: NASA

The International Space Station’s Zarya core launched from Kazakhstan on Nov. 20, 1998. The first crew arrived aboard the ISS two years later and construction of the station officially ended in 2011. The ISS is a triumph in international cooperation, although its days in low Earth orbit are numbered. Space debris, a changing political climate between the U.S. and Russia, and even black mold could all bring the ISS program to an abrupt halt. Current funding envisions the station in operation through 2024, and the aging ISS will come down in the next decade, ending more than two decades of continuous human presence in space. The Russians have expressed interest in operating the station on their own, and again, seem to have a way of making due with much less. One private U.S. space corporation, Axiom, wants to actually attach a private space station to the ISS in 2020, and detach it as a standalone station in orbit at a later date.


1. Mars Still Remains at Least 20 Years Away

We need improvements at recycling to help sustain a Mars mission.

A 2009 concept drawing of a Mars base. Credit: NASA

Like the promise of nuclear fusion, the “first human on Mars” seems to be a moving target always 20 years out. Once the U.S. beat the Soviets to the Moon, the halcyon days of Apollo just didn’t carry over to Mars exploration by astronauts. Should we really pin our hopes on a reality TV-based concept, such as Mars One? The Mars One and other concepts are counting on the progression of SpaceX technology, and the private space company may finally launch its Falcon 9 rocket later this year … although it still relies heavily on NASA support. NASA’s plans for putting the first boot prints on Mars currently target the mid-2030s, although this timeline will need to weather the uncertainty in funding brought by each new presidential administration.

As we’ve outlined before, there are plenty of challenges in sending a crewed flight to Mars. Some space exploration proponents advocate that we should return to the Moon first, a much easier place for a permanent outpost that’s only days away from rescue and resupply. That would only further postpone any venture to the Red Planet. Don’t be surprised to find 10 years from now that a Mars mission is still 20 years away.

Written by

David Dickinson is a backyard astronomer, science educator and retired military veteran. He lives in Hudson, Fla., with his wife, Myscha, and their dog, Maggie. He blogs about astronomy, science and science fiction at www.astroguyz.com.