Atmospheric Reentry Demonstrator
The Advanced Reentry Demonstrator (ARD) was a European Space Agency (ESA) suborbital reentry vehicle. It was developed and operated for experimental purposes, specifically to validate the multiple reentry technologies integrated upon it and the vehicle's overall design, as well as to gain greater insight into the various phenomenon encountered during reentry.
The ARD only performed a single spaceflight. On 21 October 1998, the vehicle was launched upon the third flight of the Ariane 5 expendable launch system. Reaching a recorded altitude of 830 km, the ARD performed a guided reentry back to Earth before splashing down relatively close to its intended target point in the Pacific Ocean after one hour and 41 minutes of flight. Following its recovery and subsequent analysis, the vehicle was found to have performed well, the nose cone and heat shield thermal protection having remaining in an ideal state and having remained completely airtight and perfectly intact.
The ARD was the first guided sub-orbital reentry vehicle to be manufactured, launched and recovered by Europe.[1][2] One of the core purposes of the mission was the gathering of knowledge that could be subsequently used during the development of future re-entry vehicles and precise landing capabilities. In the aftermath of the programme, the ESA decided to embark on a follow-up reentry demonstrator, known as the Intermediate eXperimental Vehicle (IVX). The first IXV vehicle underwent its first successful test flight during February 2015. The ARD and IVX demonstrators are intended to serve as developmental stepping stones towards a vehicle called Space Rider, meant to be the first of a series of production-standard spaceplanes.
Development
From the 1980s onwards, there was growing international interest in the development of reusable spacecraft; at this time, only the
The ARD was developed and operated as a cooperative civilian space programme under the oversight of the ESA; it fell within the agency's Manned Space Transportation Program (MSTP) framework.
The prime contractor selected to perform the ARD's development and construction was French
It has been claimed that even early on, the programme schedule was relatively tight and funding was limited.[1] According to the ESA, the restrictive financing of the programme was an intentional effort, to prove that such a vehicle could be demonstrated with a smaller budget than previous efforts had been.[2]
The experience and data obtained through ARD and IVX demonstrators are serving as developmental stepping stones towards a vehicle called Space Rider.
Design
The ARD is an unmanned 3-axis stabilised automated capsule which served as experimental reentry vehicle primarily for technology-proving and data-gathering purposes.[2] In terms of its shape, the vehicle bares an external resemblance to a 70 per cent-scale version of the American Apollo capsule, and considered by the ESA to be a 50 per cent-scale vehicle of a prospective potentially operational transportation vehicle; as such, it is 2.8 meters in diameter and weighs 2.8 tons at atmospheric interface point.[1][2] The ARD possesses an air- and water-tight pressurised structure primarily composed of an aluminium alloy, which is protected by a layer of Norcoat 62250 FI cork composite tiles across the exterior of nosecone and by an arrangement of aleastrasil silicon dioxide-phenol formaldehyde resin tiles over the heat shield. The vehicle itself can be divided into three distinct sections: the frontshield section, the rear-cone section and the backcover section.[1][2]
The ARD possesses manoeuvrability capabilities during re-entry; a favourable
During its reentry into the atmosphere, the ARD's heat shield is exposed to temperatures reaching as high as 2000 °C and a heat flux peaking at 1000 kW/m2, resulting from the
The vehicle is equipped with a Descent Recovery System (DRS), deployed prior to splashdown in order to limit the impact loads and to ensure its flotation for up to 36 hours.
The internal space of the ARD and was packed with the most advanced technologies to test and qualify new technologies and flight control capabilities for atmospheric reentry and landing.
Operational history
The ARD only performed a single spaceflight. On 21 October 1998, the ARD was launched upon the third flight of the
The ARD was recovered roughly five hours following splash down. Following recovery, the vehicle was transported back to Europe and subject to detailed technical analysis in order to acquire more information on its performance. Engineers analysing data from its sub-orbital flight reported that all the capsule's systems had performed well and according to expectations; analysis of the craft's real-time
Following post-mission analysis of the ARD's performance, it was announced that all of the demonstration and system requirements of the programme had been successfully achieved.[1] The test flight itself was described as having been "nearly nominal", particularly the trajectory and flight control aspects; additionally, many of the onboard systems, such as the navigation (primary and backup), propulsion, thermal protection, communication, and DRS were found to have performed either as predicted or to have been outside these predictions by only a small margin.[1] During reentry, the heat shield temperature reached a recorded peak temperature of 900 °C; nevertheless, both the vehicle's cone and heat shield thermal protection were found in a perfect state following its retrieval.[1]
Issues highlighted during analysis included the role of design uncertainties having led to difficulties in observing some physical phenomena such as real gas effects, addressing aerothermal environment characterization was also hindered due to the premature failure of some thermocouples. Overall, the flight was stated to have brought a great amount of high quality aerodynamic information back which, amongst other benefits, served to confirm and enhance the capabilities of ground-based prediction tools.[1] Since its retrieval and the conclusion of post-mission examination, the sole ARD vehicle itself has been preserved and has become a publicly-accessible exhibit at the European Space Research and Technology Centre in Noordwijk, Netherlands.[1]
See also
- IXV, follow-up ESA reentry demonstrator, tested in February 2015.
- OREX, equivalent Japanese demonstrator from 1994, developed and flown by NASDA
- GSLV Mk IIILVM 3X
References
- ^ a b c d e f g h i j k l m n o p q r s t u v w Tran, Phillipe., J.C. Paulat and P. Boukhobza. "Re-entry Flight Experiments Lessons Learned – The Atmospheric Reentry Demonstrator ARD." Archived 2022-12-19 at the Wayback Machine EADS Space Transportation, 1 June 2007. OMB No. 0704-0188.
- ^ a b c d e f g h i j k l m n o p q r s "The Atmospheric Reentry Demonstrator." European Space Agency, October 1998. BR-138.
External links
- EADS ARD web page
- ESA ACRV review Archived 2007-09-29 at the Wayback Machine
- ARD drop test from a stratospheric balloon performed in Southern Italy in 1996