The shoot down of American pilot Gary Powers and his U-2 in
1960 underscored the danger to human pilots during reconnaissance missions
(Sullivan, 2013). The political turmoil
associated with the capture and detention of a U.S. citizen fueled the desire
to reduce this liability. This debacle
fueled a drive toward the use of Unmanned Aerial Vehicles (UAV), starting with
the 1965 Lockheed D-21.The D-21 was essentially a ramjet engine a blended wing
body and a camera.
The D-21 could not
launch on its own, but instead was carried aloft on the back of the M-21
Blackbird (a specially configured SR-71).
However, it would ultimately reach speeds of Mach 4 at 80,000 feet MSL
(PBS NOVA, 2005). Design elements used
on the D-21 are still found today in its descendants, like the B-2 Spirit and
the F-117 stealth fighter (The Museum of Flight, 2010). The D-21 used low observable technologies
like radar-absorbing paint to evade detection.
When coupled with other design elements, like high speed and altitude
capabilities, the D-21 could operate in dangerous territories without being
detected or shot down (The Museum of Flight, 2010). The D-21 flew a
preprogrammed mission profile afterwards returning to uncontested airspace to
release its film payload before self-destructing (The Museum of Flight,
2010).
As detection technology has
become more sophisticated, human pilots are at even more risk and the UAS are
more valuable than ever. One of the
latest evolutions based on this reality is the Lockheed-Martin RQ-170 Sentinel,
first introduced in 2007 (Militaryfactory.com, 2013). The RQ-170 Sentinel (Beast of Kandahar) is a
top secret UAS that looks like a small B-2 Spirit, so the specifications are
only speculative (Johnson, 2009).
However, this reconnaissance platform has come a long way since its 1965
grandparent. Right from the start, the
RQ-170 is able to taxi and take-off from a runway just like any other
airplane. It still incorporates
low-observability technology like radar absorbent paint, but it relies less
upon speed and altitude to evade detection.
The turbofan engine incorporated into the flying wing design would make
supersonic flight unlikely, though its expected ceiling of 50,000 feet MSL
exceeds other UAS platforms like Reaper and Predator (Militaryfactory.com,
2013). It has suspected performance
characteristics similar to modern fighter-types (Militaryfactory.com,
2013). The Sentinel has another massive
advantage over its ancestor the D-21; the Sentinel can return and land! Forecasting into the future can be a tricky
business, but one thing seems for sure; the UAS is here to stay. As the systems continue to evolve, it would
seem that lower cost radar evasion technologies are preferential to
edge-of-the-envelope performance.
References:
Johnson, M. (2009,
December 15). Out of Nevada comes 'Beast' | Las Vegas Review-Journal.
Retrieved from Reviewjournal.com Web site: http://www.reviewjournal.com/news/out-nevada-comes-beast
Militaryfactory.com.
(2013, July 2). Lockheed Martin RQ-170 Sentinel - Unmanned Aerial Vehicle.
Retrieved from Military Factory.com Web site:
http://www.militaryfactory.com/aircraft/detail.asp?aircraft_id=896
PBS NOVA. (2005, Fall).
NOVA | Spies That Fly | D-21 (USA) | PBS. Retrieved from NOVA Web site:
http://www.pbs.org/wgbh/nova/spiesfly/uavs_10.html
The Museum of Flight.
(2010, December 29). Lockheed D-21B Drone - Manufacturer was Lockheed.
Retrieved from The Museum of Flight Web site:
http://www.museumofflight.org/aircraft/lockheed-d-21b-drone
