NASA sets Ares test flight roadmap

by Chris Bergin

Details of the first two test flights for the next generation Ares launch vehicle are beginning to come to light.

The first Ascent Development Flight Test (currently referred to as ADFT-0) will be the first test of the new Crew Launch Vehicle (Ares I-1) and will not fly any earlier than September 2008.

A second flight is planned to validate the results, which will occur six months after.

 *Full document, info and images available on L2*

While testing some flight hardware systems is an obvious aspect to these tests, NASA intends to use these test flights to gather a lot more valuable information about the processing of the vehicles.

From stacking procedures inside the VAB and servicing at the Pad, to Parachute performance and SRB recovery operations of the larger booster stage, these flights will provide engineers with their first real-world opportunity to begin familiarizing themselves with the new vehicle – and start training and certification programs for the barrage of new procedures. They will also offer the first hand opportunity to identify which procedures, facilities and equipment will require modification to support later flights in the new program.

For KSC in particular, the second flight is deliberately challenging; Ares I-2 is intended to test their ability to turn-around a second CLV vehicle within six months of the  first, while also preparing the four Space Shuttle missions manifested for 2009 at the same time. The results of this scheduling test will provide much needed useful data  to NASA to be used throughout the new program.

Flight Hardware:

The new 5-segment variant of the Space Shuttle SRB’s will not actually be ready in time for these flights. NASA intends to utilise a standard 4-segment booster with an empty ‘dummy’ fifth segment mounted on top, to simulate the correct aerodynamic, mass and center-of-gravity properties of the final design. The design has been selected to mainly simulate the configuration during the post-separation phase of the flight.

Above the booster, the pilot, drogue and larger main parachutes will be housed in a series of skirts, topped (possibly) by a new ‘Aero Shell’ cover intended to protect the  ‘chutes from any damaging blast produced when the Upper Stage main engine is ignited immediately after separation occurs. These test flights will provide the first  opportunity to gather hard data on how a 5-segment SRB tumbles away after separating from a single-stick configuration launcher.

These flights will also provide valuable data for both the Recovery Ships and the SRB-Slip facility at the Cape, regarding recovery operations of an SRB stage noticeably longer than previously used, and with considerably larger parachutes.

Above the SRB will be a Frustum, whose purpose is to offer a tapered transition between the 3.7m diameter core of the SRB, out to the 5.5m diameter of the Upper Stage.  When the SRB separates and falls away, the Frustum remains attached briefly to the Second Stage, and when safely clear, it too will be separated to fall away into the ocean.

Next comes a new Reaction Control System (RCS) in the Interstage. This new system is planned to solve the complicated issue of roll-control for the new vehicle. Based on a scaled-up Post-Boost Propulsion System (PBPS), originally made by Rocketdyne for the ‘Peacekeeper’ Inter-Continental Ballistic Missile (ICBM), the new system will consist of a total of 72 small hypergolic (monomethylhydrazine fuel and nitrogen tetroxide oxidizer) thrusters located in two clusters of 36.

Each cluster is mounted opposite the other on the sides of the Interstage. By controlling the firing of different numbers of these simple and already flight-certified thrusters, very precise roll-control can be achieved. It is not clear from available documentation yet, whether the Interstage will separate from the Upper Stage on these test flights, although for operational flights later in the program, it will be separated swiftly.

Above that will be the Upper Stage Simulator (USS), designed to mimic very accurately the shape, mass and center-of-gravity of a real Upper Stage, with a set of Development Flight Instrumentation (DFI) systems, TV cameras and other equipment, will provide flight data throughout the test flights.

A few different designs appear to exist at this point, but it seems likely that the final design of the USS will consist of an accurate mass model of the J-2X main engine at the bottom, a large water tank to simulate the mass of the propellant, and a series of identical segments, referred to as ‘Tuna Cans’, which are designed to allow full access to the inside of the stage, and which are designed to easily join together and be assembled by workers inside, without the need of any new external work platforms in the VAB or at the Pad. The USS is not being designed to be recovered after the flight.

Detailed mass models of the final parts will be constructed to be placed on top. A Spacecraft Adapter (SCA), the CEV Service Module (SM), CEV Command Module (CM) and Launch Abort System (LAS) will be constructed, again accurate in terms of shape, mass and c-of-g. None of these elements are planned to be recovered.

Early versions of the Avionics systems will be aboard both the First stage and the Upper Stage Simulator. They will be designed to fly the various stages as accurately as possible, collect data from all the various systems throughout the vehicle by both radio signal and hard-wire backups to ensure data is received, and then to transmit the data back to Launch Control.

From there NASA appears to be planning to provide the data live to both Marshall Space Flight Center (MSFC) in Huntsville AL and also Mission Control at the Johnson Space Center (JSC) in Houston, TX.

Vehicle Assembly Building (VAB):

The facilities at the Kennedy Space Center (KSC), for Space Shuttle Operations, are extensive and very complex, so it has been NASA’s goal to minimise the alterations as much as possible in order to support these two test flights while the Shuttle continues to fly. The intention is to gather the maximum possible amount of information  regarding what changes will be required to support later flights once the Shuttle Program comes to an end, sometime before the end of 2010.

So far in the planning, there does not appear to be any requirement to modify facilities in the VAB at all to support the ADFT-0 flights. Standard Space Shuttle Work  Platforms in either High Bay 1 or High Bay 3 can be used to assemble the lower sections of the ADFT-0 vehicles. The upper sections of these test articles are being cleverly designed in order to allow all attachments to be performed by personnel working inside the vehicle itself, thus not requiring any expensive work platform modifications, and guaranteeing not to hinder Shuttle operations in any way.

Current Assembly Sequence:

* The first four segments of the SRB will be assembled over the left hole of the MLP, exactly the same way as for a standard Space Shuttle mission.
* The empty fifth SRB segment will be attached to the parachute skirts, the Frustum and the Interstage in the transfer aisle, making a complete sub-assembly.
* That entire sub-assembly will then be hoisted and attached to the top of the waiting 4-segment booster
* The lower part of the Upper Stage Simulator (USS), containing the J-2X mass model and water tank will be next to be mounted on top
 NOTE: To this point current Shuttle work platforms inside the VAB can support all assembly work
* Two identical ‘Tuna Can’ USS segments will be attached on top, and will be secured in place by personnel working inside the vehicle
* The mass modelled Spacecraft Attachment (SCA) ring, CEV’s Command Module (CM) and Service Module (SM) and Launch Abort System (LAS) are all assembled in the transfer aisle and attached as another complete sub-assembly, again by personnel working inside the Upper Stage.
* The vehicle is completely checked-out, and rolled to the Pad

New procedures, new training and new certification programs will be created for the new vehicle, but largely they will be based on tried and tested heritage in use today on the Space Shuttle program, and also during the historic Apollo program.

Launch Pad:

As has been announced already on this site, NASA intends to release Launch Complex 39B (LC-39B) from the Space Shuttle Program on 31st March 2007, and reassign it to the Constellation Program immediately thereafter. The Pad structures require a number of alterations in order to support these new-configuration launch vehicles, so work will begin immediately after the handover to prepare the Pad for the ADFT-0 flights.

Firstly, at a little over 95m tall, the CLV is considerably taller than the 56m Space Shuttle Stack, so modifications are required to protect the new vehicle from lightning strikes. While a number of solutions are being considered, it is likely that the current lightening mast will be extended by more than 30m in height.

Also, for access to the vehicle, the current Gaseous Oxygen (GOX) Vent Arm will be redesigned (including the removal of the famous ‘Beanie Cap’) to allow workers to enter the vehicle around the Interstage area. This will provide access for servicing the Avionics of the Upper Stage, the Hypergolic propellant for the RCS system and most other general maintenance, as well as electrical, hypergolic fuelling and ECS connections.

The area around the SRB’s 5th segment will be accessible via the modified Crew Service Arm if required, and this arm will also provide ECS cooling of the First Stage Avionics packages.

The Rotating Service Structure will remain at the Pad, but there are no plans to utilise it.

Mobile Launcher Platform:

One of the Space Shuttle Program’s massive Mobile Launcher Platforms (MPL), specifically MLP-1, will be reassigned permanently to the Constellation Program on 1st March 2008. The remaining Shuttle flights after that point will continue to utilise just MLP-2 and MLP-3, flying out of LC-39A.

The MLP will remain largely unchanged from its Space Shuttle configuration, even with the familiar Tail Service Masts staying in place. No Launcher/Umbilical Tower (LUT) is required for these flights, and no damper is expected to be required during roll-out.

Because the First Stage is the only major powered section in these tests, most electrical connections between the ground and the vehicle are intended to be made through the current SRB Aft Ground Carrier Assembly (GCA), which will provide Rise-off Umbilical interfaces for all connections.

This configuration is well within the capabilities of the current Crawler Transporters to move, so they will require no modification at all to support the ADFT-0 flights.

Other KSC Facilities:

For the test flights themselves, Launch Control Center Firing Room number 1 will be utilised, although it is not being officially handed over to the Constellation Program.

And finally, do not get too familiar with the acronym ‘ADFT’, NASA clearly states in documentation received by, that they intend to ‘Create a new name for this flight test’, so watch this space for the new name as soon as we have it.

ARTICLE 2 IN THIS SERIES WILL CONTAIN: ADFT-0 Costs, Risks and Pending Analysis Work.

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