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Advanced Soaring Concepts Apex

Advanced Soaring Concepts · Experimental high-altitude research sailplane · Modern (1992–2009)

Advanced Soaring Concepts Apex — Experimental high-altitude research sailplane
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The ASC Apex (Advanced Soaring Concepts Apex) was a piloted high-altitude sailplane designed to investigate flight characteristics in the thin upper atmosphere relevant to a Mars-aircraft mission concept. NASA Dryden flew the Apex twice in 1997 from Edwards AFB, both flights ending in landing accidents that prompted the programme's cancellation. The aircraft survives in private collection.

The configuration was a high-performance sailplane with a 60-ft wingspan and a pressurised cockpit, built by ASC of Mojave, California. The intent was to fly the airframe under tow to about 100,000 ft (30,500 m) using a high-altitude balloon, then release for an unpowered glide back to Edwards. At 100,000 ft the atmospheric density is about 1% of sea-level — close enough to the surface density of Mars (~6 millibar) to give engineers a flight-test analogue for a future Mars Aircraft mission.

The first flight (3 May 1997) ended in a hard landing that damaged the right wing. The aircraft was repaired and re-flown on 23 September 1997; this flight ended with another hard landing that broke the airframe back. NASA pilot Dana Purifoy was uninjured both times. The high-altitude flight envelope had not yet been reached — both flights were low-altitude balloon-tow tests aimed at validating the Apex flight handling under tow before attempting the full 100,000-ft profile. After the second accident NASA cancelled the programme, citing repair costs and uncertainty about whether the airframe could be made consistently safe on landing.

The Apex's data set was incomplete; the high-altitude Mars-density flight envelope was never reached. NASA's Mars-aircraft concept work shifted to other vehicles (sounding rockets, ARES Mars airplane mockups, eventually the Ingenuity rotorcraft). The Apex airframe was sold to private owners after the programme's cancellation; it is not on public display.

For Kids — a shorter, friendlier version

The ASC Apex was a special glider built to help scientists learn about flying on Mars. It had no engine. It was designed to soar through very thin air, just like the air on Mars. A team in Mojave, California built it for NASA.

The Apex had a wingspan of 60 feet. That is wider than many small houses! It also had a sealed cockpit to protect the pilot from the cold, thin air high above Earth. NASA flew it from Edwards Air Force Base.

To get the glider up high, a giant balloon lifted it to about 100,000 feet. At that height, the air is very thin — only about one percent as thick as air at ground level. That is close to how thin the air is on Mars. So flying there was almost like flying on Mars!

NASA flew the Apex twice in 1997. Both flights ended with hard landings that damaged the plane. The pilot, Dana Purifoy, was not hurt either time. After two accidents, NASA stopped the programme. The Apex still exists today in a private collection.

Fun Facts

  • The Apex glider had a wingspan wider than a basketball court is tall!
  • It had no engine at all — it glided all the way back to the ground on its own.
  • A giant high-altitude balloon carried the Apex up to about 100,000 feet before release.
  • At 100,000 feet, the air is so thin it is almost like being on the surface of Mars.
  • The Apex flew twice in 1997, and both flights ended with hard landings.
  • The pilot was not hurt in either landing accident.
  • NASA used the Apex to plan for a future aircraft that could fly on Mars.
  • Even though the programme ended, the Apex glider still exists in a private collection today.

Kids’ Questions

Why did NASA fly a glider so high up?

At very high altitudes, the air is super thin. That thin air feels a lot like the air on Mars. By flying there, engineers could learn how a plane might work on Mars one day.

How did the Apex get up to 100,000 feet without an engine?

A huge balloon carried the Apex all the way up. Then the pilot released the glider and flew it back down to the ground on his own, with no engine at all.

Why did NASA stop the programme?

Both test flights in 1997 ended with hard landings that damaged the plane. After two accidents, NASA decided to cancel the programme. The pilot was safe both times, though.

Where is the Apex now?

The Apex glider still exists today. It is kept in a private collection. So even though it never flew again, it was not thrown away or destroyed.

Variants

Apex (single airframe)
60-ft wingspan high-performance sailplane with pressurised cockpit. Two flights in 1997, both balloon-towed low-altitude validation flights ending in landing damage. Airframe sold to private owners after programme cancellation.

Notable Operators

NASA Armstrong (Dryden) Flight Research Center
Sole operator. Pilot Dana Purifoy made both 1997 flights. Programme cancelled after the second landing damage incident.

Frequently Asked Questions

Why was the Apex built for high altitude?

The 100,000-ft target altitude has atmospheric density of about 1% of sea level — close to the surface density of Mars (~6 millibar). Flying a piloted sailplane in that envelope would have given NASA a flight-test analogue for a future Mars Aircraft mission concept.

Did the Apex ever reach high altitude?

No — both 1997 flights were low-altitude balloon-tow validation tests aimed at proving handling characteristics before attempting the full 100,000-ft profile. The programme was cancelled after the second flight's landing accident, before the high-altitude phase was attempted.

What is a Mars Aircraft?

A proposed unmanned aerial vehicle that would fly through the Martian atmosphere — roughly equivalent to flying at 100,000 ft on Earth. Several concepts have been studied (ARES, Mars Cessna, etc.) but none have been launched. The Ingenuity rotorcraft (delivered 2021) is the only flying-machine NASA has actually flown on Mars.

Why was the Apex programme cancelled?

Both 1997 flights ended in landing damage — the first broke the right wing, the second broke the airframe back. NASA judged that repair costs and the uncertainty about whether the airframe could be made consistently safe in landing made continuation uneconomical.

Where is the Apex now?

Sold to private owners after NASA's 1997 cancellation. The airframe is not on public display. ASC (the builder) continues to operate from Mojave, California.

Sources

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