60 years after U.S.’s first satellite success, space program thriving

by William Graham and Chris Gebhardt

At 22:47:56 EST on Friday, 31 January 1958 (03:47 UTC on 1 February), a Juno I rocket lifted off from Cape Canaveral’s Launch Complex 26A and successfully placed the Explorer 1 satellite into orbit around the Earth.  The launch made the United States the second country to place a satellite into orbit – four months after the Soviet Union orbited Sputnik 1.  Sixty years laters, the state of the US launch industry is strong thanks in large part to the proliferation of new commercial entrants into a long-standing market.

Explorer 1 – America’s first successful satellite launch:

The launch of Explorer 1 was America’s second attempt to place a satellite into orbit.  Nearly two months previous on 6 December 1957, a Vanguard rocket exploded at liftoff when making the nation’s first attempt.  It’s failure, in full view of the world’s media, compounded the embarrassment of being beaten into orbit by two Sputnik satellites from the USSR as the Space Race began.

In 1955, the United States had committed itself to placing a satellite into orbit during the International Geophysical Year, which ran from 1 July 1957 to 31 December 1958.  The Naval Research Laboratory’s Vanguard rocket had been chosen to perform the launch as it was derived from Viking, a sounding rocket, as opposed to a missile.

A Vanguard rocket fails on the launch pad shortly after liftoff on the US’s first attempt to place a satellite into orbit on 6 December 1957. Credit: NASA

After Vanguard’s failure, the US turned to the Army Ballistic Missile Agency (ABMA), an agency within the US Army dedicated to missile development, and Explorer 1 was eventually launched by the ABMA in conjunction with the Jet Propulsion Laboratory (JPL).  

The Juno I rocket that carried Explorer 1 into orbit was a four-stage version of the Jupiter-C test vehicle, which was itself derived from the PGM-11 Redstone missile.  The Redstone was an early nuclear-capable short-range ballistic missile (SRBM) and was a development of the V-2 rocket which had been employed by Nazi Germany during the Second World War.

At the end of the war, many of Germany’s leading rocket scientists, including Wernher von Braun, the V-2’s principal designer, and his team surrendered to the United States.  Under Operation Paperclip, these scientists were brought to the US to help advance the nation’s military technology against the backdrop of the Cold War.

For the Explorer 1 launch, Jupiter-C incorporated a stretched Redstone as its first stage, with its second and third stages consisting of clustered solid rocket motors derived from the MGM-29 Sergeant missile.

The Explorer 1 satellite itself was actually built around a Sergeant rocket motor, which served as the Juno I’s fourth stage.  The cylindrical satellite had a mass of 13.97 kilograms (30.80 lb) and measured 203 centimetres (79.9 inches) in length and 15.2 centimetres (5.98 inches) in diameter.

After launch was completed, Explorer 1 was found to be in a 358-by-2,550-kilometre (222 x 1,584 mile, 193 x 1377 nautical mile) orbit, inclined 33.24 degrees to the equator, in which it completed one revolution of the Earth every 114.8 minutes.  The spacecraft remained in orbit until 31 March 1970.

Unlike its two Sputnik predecessors, Explorer 1 was the first satellite to research the space environment via instruments, which included a Geiger counter, sensors to monitor the temperature of the spacecraft, and two payloads – an acoustic sensor and an erosion wire grid – to detect micrometeoroid impacts.

To relay the results of its experiments to the ground, Explorer 1 carried two transmitters consisting of a 60-milliwatt amplitude-modulated (AM) transmitter and a 10-milliwatt phase-modulated (PM) transponder.  

Explorer 1, the US’s first satellite. Credit: NASA

Data returned by Explorer 1 proved that a belt of charged particles was trapped within Earth’s magnetic field.  While the existence of radiation belts had previously been theorised, Explorer 1 made their discovery, a result which was corroborated by the follow-up Explorer 3 mission two months later.  

The radiation belts would become known as the Van Allen Belts, after Dr. James A. Van Allen of the University of Iowa, who was the mission’s principal investigator.

Explorer 1 was battery-powered and functioned successfully for nearly four months, ceasing operations once its batteries were depleted.

Explorer 1 was the first satellite of what would become NASA’s Explorer programme.  The name Explorer has continued to be used for NASA’s small scientific research missions, with the most recent satellite in the series – IRIS, or Explorer 94 – launched in June 2013.

The next mission in the Explorer series is ICON (Ionospheric Connection Explorer), due for launch at the end of February.

Sixty years on, state of the US space program is strong:

Public support and perception of the US space program has always been a prominent factor in US space operations since their commencement in the 1950s.  As with any long-running program, those perceptions and support have ridden a wave of enthusiasm and highs as well as troughs of depression and concern.

At no point has public support and perception of the US space program been stronger than at the end of the 1960s when NASA succeeded in landing Apollo 11 on the surface of the Moon and Neil Armstrong and Buzz Aldrin took the first steps for humanity on a world other than Earth.

The public nature of the US space program has – above all – provided an immense source of pride, elation, and joy for not just its successes and invaluable scientific exploration efforts, but also for its recovery from failure.

From early failures that eventually led to the first US astronauts reaching space, these recoveries from failures and missteps have been one of the cornerstones of the US space program’s interaction with the public – with the rousing success of Apollo 11 following the tragedy of Apollo 1, with the return to flight of the Shuttle and creation of what would become the International Space Station following the Challenger disaster, and the decision to foster the addition of more commercial companies to the launch community following the Columbia accident.

While NASA is currently transitioning its ability to launch astronauts from the United States from government-owned rockets to commercially built and contracted rockets and capsules, both of the companies with which NASA has those contracts – SpaceX and Boeing – are slated to debut their new crew capsules in uncrewed demo flights this year.

For SpaceX, this demonstration is set to continue a highly successful string of impressive records the company has achieved over the last year.  In the one year period from 14 January 2017 to 13 January 2018, SpaceX accomplished an impressive 19 successful flights of their Falcon 9 flagship rocket, returning many of those boosters to successful landings on either ASDS drone ships in the Atlantic or Pacific oceans or back to Landing Zone 1 at the Cape Canaveral Air Force Station.

First Falcon 9 Booster landing at LZ-1 – Credit SpaceX

Moreover, SpaceX has now resoundingly succeeded in its goal of reusing Falcon 9 boosters, with five total reuses accomplished last year – including the very first reflight on the SES-10 mission in late March 2017.

For SpaceX, 2018 holds the potential to be just as historic and meaningful as last year.  Overall, the company has 30 missions of its Falcon family of rockets planned this year, including the highly anticipated debut next week of Falcon Heavy, the commencement of commercial crew launch capabilities, launching NASA’s Transiting Exoplanet Survey Satellite (TESS) mission, as well as numerous missions for the US government, international companies/organizations/governments, and US-based companies.

Falcon Heavy will become the world’s most capable heavy-lift rocket upon its debut, and while the company will introduce this new capability, they are also continuing to look to the future, with build operations slated to begin early this year on the company’s BFR rocket – the architecture that, based on all available plans and schedules, will be the vehicle to take us to Mars not just for short-term missions but for colonization and permanent settlement.

Meanwhile, other commercial companies are continuing to proliferate throughout the market. United Launch Alliance (ULA) is currently designing its Vulcan rocket, slated to replace the veteran Atlas V and Delta IV rocket families.  At the same time, ULA and Bigelow Aerospace are developing plans for commercial economic zones and workstations in Low Earth Orbit and cislunar space in an effort to develop a space-based economy.

Concept of a Bigelow BA 330 inflatable space station in Low Earth Orbit, with SpaceX’s Dragon and Boeing’s Starliner crew capsules docked. Credit: Bigelow Aerospace

Blue Origin is nearing completion of its manufacturing facility on Merritt Island for its upcoming heavy-lift New Glenn rocket while continuing to make extremely positive strides in the arena of suborbital, commercial spaceflight for paying customers.

At the end of 2017, Blue Origin successfully tested a new version of its New Shepard suborbital rocket and crew capsule, and the company anticipates that suborbital flights with willing test passengers could commence this year.

Meanwhile, the small satellite launch market is also set to burst onto the stage this year, with Rocket Lab, a U.S. aerospace manufacturer with a wholly owned New Zealand subsidiary, already achieving a successful orbital flight of their Electron rocket which – unannounced beforehand – placed the humanity star payload into orbit earlier this month.

Rocket Lab and Vector Space, another US company, are solely targeting the small satellite launch market, building small-scale rockets designed to place lightweight payloads into dedicated orbits.

On the government side of US space exploration, NASA continues to be a leader in space science research, with the International Space Station now in full utilization mode and a backlog of critical scientific experiments waiting for their chance to be launched to and performed on the Station.  The agency is also deep into development of the super heavy lift Space Launch System rocket – which is set to debut in 2019 or 2020.

Jupiter, as seen through JunoCam. Credit: NASA

Beyond Earth, NASA’s Juno spacecraft continues to return incredible amounts of scientific data and inspiring pictures of Jupiter, Osiris-Rex is set to arrive in orbit of asteroid Bennu later this year, and the agency’s flagship New Frontiers satellite, New Horizons, is set to make the farthest planetary object encounter in history at the end of this year/beginning of next year when it flies by Kuiper Belt Object MU69 on 31 December 2017 / 1 January 2018.

Meanwhile, the agency’s fleet of Mars explorers, both in orbit and on the surface, continue to record invaluable data about the red planet that will greatly aid humanity’s exploration and colonization efforts of our celestial neighbor.

This year will also see NASA launch the InSight mission to Mars aboard a ULA Atlas V rocket from Vandenberg Air Force Base, California… the first interplanetary mission to be launched from the west coast of the United States.

A flight-proven Falcon 9 with GovSat1/SES-16 on SLC-40 ahead of launch. Credit: Chris Gebhardt for NASASpaceflight

In short, the state of the US space program is strong, perhaps stronger than ever as numerous commercial and government agencies push our boundaries of knowledge, exploration, and technology for the betterment of the future.

Today, on the 60th anniversary of Explorer 1’s launch in 1958, it is somewhat fitting that SpaceX, arguably the US-based space company creating the most interest in space exploration presently, is scheduled to launch a flight-proven Falcon 9 rocket from a launch pad just a few miles from where Explorer 1 first left Earth.

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