Booking Environmental Test Lab Time for Space and Defense Hardware
Buying test lab time means reserving a shaker, chamber or EMI room at an outside lab to run qualification, protoflight or acceptance tests to a standard such as GSFC-STD-7000 (GEVS), SMC-S-016 or MIL-STD-461. Aerospace Sourcing takes your test request, finds labs with the capability and schedule to fit, and coordinates fixtures, paperwork and reports under one purchase order.
What test lab time covers
It covers environmental and electromagnetic testing that proves hardware survives launch and works in its mission environment, run at a lab you do not own. Programs buy outside time when their own facilities are booked, too small, missing a capability or not worth building for one campaign.
The tests buyers ask for most often:
- Sine vibration to simulate low frequency launch loads and to find resonances with low level sine sweeps before and after other tests
- Random vibration to simulate launch vibration and to screen workmanship
- Shock, including mechanical shock and pyroshock from separation events
- Acoustic testing for large, lightweight structures that respond to sound pressure
- Thermal vacuum testing that cycles hardware between hot and cold limits under vacuum while it operates
- Thermal cycling at ambient pressure, often used as a cheaper workmanship screen at lower levels of assembly
- EMI and EMC testing of conducted and radiated emissions and susceptibility
Defense equipment that is not going to space often adds MIL-STD-810H methods such as humidity, salt fog, sand and dust, and temperature shock. MIL-STD-810H is a tailoring standard rather than a fixed set of levels, so the test plan has to define the profile.
The standards that set the levels
Your program's verification plan sets the levels, and it usually points to one of a few standards. Know which one before you call a lab, because it changes the test sequence, levels, durations and margins.
GSFC-STD-7000, the General Environmental Verification Standard
GEVS is NASA Goddard's baseline for showing by test and analysis that hardware will perform in its mission environments and meets minimum workmanship standards. Revision B was approved on April 28, 2021. NASA lists it as active but not a NASA mandatory standard, so it applies when a program or contract invokes it. A few of its figures that drive lab selection:
- Its generalized random vibration levels for components of 22.7 kg (50 lb) or less on expendable launch vehicles are 14.1 Grms overall for qualification and protoflight and 10.0 Grms for acceptance, with a formula to reduce levels for heavier components.
- For non-cryogenic flight hardware it prescribes a minimum of 12 thermal cycles before flight, accumulated across levels of assembly.
- It refers to a minimum of 8 thermal vacuum cycles for qualification.
- Its EMC section is built on MIL-STD-461G test methods with GSFC tailoring.
SMC-S-016
SMC-S-016, dated September 5, 2014, sets environmental and structural ground test requirements for launch vehicles, upper stages, space vehicles and their subsystems and units. It is common on Space Force and other national security space programs. It makes qualification testing of dedicated hardware the baseline, followed by acceptance testing of flight hardware to screen workmanship. It is written to be tailored, and The Aerospace Corporation published a tailoring of it in 2020.
MIL-STD-461G
MIL-STD-461G, dated December 11, 2015, sets electromagnetic interference emission and susceptibility requirements and the methods to verify them for equipment and subsystems used by DoD. It fits best at the level of electronic enclosures no larger than an equipment rack and their interconnecting cables, and is not meant to be applied directly to modules inside an enclosure or to whole platforms. Labs often hold accreditation for some of its test methods and not others, so check the specific methods.
Other documents you may see
NASA-STD-7001 sets vibroacoustic test criteria for payloads and NASA-STD-7003 sets pyroshock test criteria. Check the revision your program invokes, because both have been revised over time.
Qualification, protoflight and acceptance
The test strategy decides the levels and how many units you test. Get it settled before booking time.
| Strategy | What is tested | Purpose |
|---|---|---|
| Qualification | A dedicated unit that will not fly | Proves the design with margin above expected flight levels |
| Protoflight | The flight unit itself | Combines design proof and workmanship screening on the unit that will fly |
| Acceptance | Each flight unit built after the design is qualified | Screens workmanship and proves performance at flight levels |
GEVS also notes that hardware with beryllium, composite, ceramic or bonded joints in the load path, where margins are driven by vibroacoustic loading, should be tested at protoflight levels for random or acoustic testing even when the design was already qualified. That kind of rule changes how much test time you need, so read the standard your program invokes.
How to check a lab before you book
Match the lab's equipment, accreditation and handling rules to your hardware and your test plan. A lab can be excellent and still wrong for your test.
- Shaker force and table size. The shaker has to drive the mass of your unit plus fixture to the required level across the frequency range. Send the mass, center of gravity and footprint.
- Fixtures. Vibration fixtures need to be stiff across the test range. Ask who designs and builds the fixture and whether a fixture survey is included.
- Chamber size and capability. For thermal vacuum, confirm the chamber's usable volume, temperature range, vacuum level, shroud and platen control, and feedthroughs for your power, data and thermocouples.
- Accreditation scope. ISO/IEC 17025 accreditation is granted method by method, not as a general statement of competence. Read the lab's scope document for the exact methods you need, such as specific MIL-STD-461G or MIL-STD-810H methods.
- Calibration. Accelerometers, load cells, thermocouples and EMI receivers should be in calibration, with records available.
- Cleanliness. Spacecraft hardware is usually built and tested in controlled environments classified under ISO 14644-1. Confirm the cleanliness of the lab's handling areas and whether the chamber has been baked out or certified for your contamination limits.
- Export control and security. If the hardware or test data is controlled, confirm that only US persons will handle it and that data leaves the lab by an approved method.
- Witnessing. Plan for customer, prime or government witnesses and their access requirements.
Cleanrooms and contamination control
Flight hardware usually has to stay inside a controlled environment from the time it arrives at the lab until it is packed again, so the lab's cleanroom class matters as much as its shaker. ISO 14644-1 classifies cleanrooms from ISO Class 1, the cleanest, to ISO Class 9 by the number of airborne particles per cubic meter. ISO Class 8 allows up to 3,520,000 particles of 0.5 micrometers or larger per cubic meter, and ISO Class 7 allows 352,000.
Spacecraft integration is commonly done in ISO Class 7 or 8 rooms, and COSPAR planetary protection guidance sets ISO Class 8 as a minimum for building and testing spacecraft, with cleaner rooms for hardware that will contact a planetary surface. Your contamination control plan sets the real requirement, including particle and molecular limits inside the test chamber. Send that plan with the request so the lab can confirm gowning, bagging, chamber bakeout and witness sample practices before the hardware arrives.
What the lab needs from you
Send a test request a lab can price without guessing. The minimum is:
- The test specification or procedure, with the standard and revision it implements
- Test levels, durations, axes, tolerances and abort limits
- Unit mass, center of gravity, envelope, mounting interface drawing and fixture status
- Number of units and whether they are qualification, protoflight or flight units
- Instrumentation: number and location of control and response accelerometers, thermocouples and other channels
- Power, data and functional test equipment the unit needs during the test
- Cleanliness, ESD and handling requirements
- Report format and data deliverables
- Export classification of the hardware and data
- Your preferred window and the latest date that still protects your schedule
What drives test schedule and cost
Lab availability is the obvious driver, but readiness on your side often decides whether a slot is used or lost.
- Lab calendar. Large shakers, big thermal vacuum chambers and EMI chambers book up around launch campaigns.
- Fixture design and fabrication. A new vibration fixture is a machining job of its own and should start early.
- Test readiness. Procedures approved, unit functional, ground support equipment and cables ready, witnesses scheduled.
- Chamber time per cycle. Thermal vacuum time is dominated by pump down, transitions and dwells, so the number of cycles drives days in the chamber.
- Anomalies and retests. A failure or a bad fixture survey can stop a campaign while the cause is found and the test is repeated.
- Reports. Data reduction and formal reports take time after the last run.
We do not promise lab availability or dates before a lab confirms. A person replies within one business day, and rush requests are prioritized.
Where the capacity comes from
Some of the capacity we look for is spare time at labs and companies that own test equipment for their own programs and list it with us. Labs, cleanrooms and companies with idle shakers or chambers can sign up for free on our supplier page, and our page for test labs explains how selling spare capacity works.
Buyers on satellite and launch programs tend to need test time alongside fixtures, machined parts and GSE. Our pages for satellite manufacturers and launch providers cover how we support those programs, and our RFQ checklist helps when the test fixture itself needs to be built.
How Aerospace Sourcing handles a test request
We do not own test equipment. We find labs whose capability, accreditation scope and schedule fit your test plan and coordinate the work.
- One quote, one point of contact and one purchase order, even when a fixture shop, a test lab and a cleaning house are all involved
- Your test specification, handling, cleanliness and reporting requirements flowed down to the lab
- Every supplier signs a flow-down NDA before seeing your data and does not learn who you are unless you approve
- No ITAR, EAR controlled or CUI data through our website; controlled files move by secure transfer to US persons only, as described on our confidentiality page
- A certificate of conformance with every order, plus the test reports and data your request requires
Request test lab time
Use the test lab request form, which is preset for test time so it asks for unit mass, test levels and dates up front. Those three facts decide which shakers and chambers can even be considered, so sending them first saves a round of questions. A person will reply within one business day.
Questions
What is GEVS and when does it apply?
GEVS is GSFC-STD-7000, NASA Goddard's General Environmental Verification Standard. It gives baseline test levels, test options and methods for verifying payloads, subsystems and components for Goddard programs, and other programs often borrow from it. Revision B was approved in April 2021. NASA lists it as active but not mandatory, so it applies when your program's verification plan or contract invokes it.
What is the difference between GEVS and SMC-S-016?
Both set environmental test requirements for space hardware, but they come from different customers. GEVS is NASA Goddard's standard for its flight projects. SMC-S-016 is the US Air Force Space and Missile Systems Center standard, dated 2014, that covers launch vehicles, upper stages and space vehicles on national security programs. Levels, margins and test sequences differ, so use the one your contract invokes and its tailoring.
Does my hardware need MIL-STD-461 EMI testing?
If it is electronic equipment for a DoD program, MIL-STD-461 is usually invoked through the procurement specification, often with tailoring. NASA lists MIL-STD-461G as a mandatory standard for its programs, and GEVS builds its EMC section on MIL-STD-461G methods. The specific tests, such as conducted and radiated emissions and susceptibility, are chosen by your EMC requirements, not by the lab.
How do I know a lab is qualified for my test?
Read its ISO/IEC 17025 scope of accreditation for the exact methods you need, because accreditation is granted method by method. Then check equipment capability against your unit mass and levels, calibration records, fixture approach, cleanliness of handling areas and how it handles controlled hardware and data. Ask for a sample report so you know the data you will receive.
Can you find thermal vacuum time on short notice?
Sometimes. It depends on chamber size, temperature range, vacuum level and how many cycles you need, since cycle count drives days in the chamber. We look at labs that list spare capacity with us and at other qualified labs. We do not promise dates before a lab confirms, but a person replies within one business day and rush requests are prioritized.
Who designs the vibration fixture?
Either your team, the lab or a separate shop, and it should be decided before booking time. The fixture must be stiff enough across the test frequency range not to distort the input, and many test plans call for a fixture survey before the unit is mounted. If the fixture needs to be machined, we can source it with the test time under the same purchase order.
Related
Sources
- NASA Technical Standards System: GSFC-STD-7000 GEVS
- GSFC-STD-7000B General Environmental Verification Standard (2021)
- EverySpec: SMC-S-016 (5 September 2014) Test Requirements for Launch, Upper-Stage and Space Vehicles
- DTIC: Tailoring of SMC-S-016 (2014), Aerospace Corporation
- EverySpec: MIL-STD-461G
- NASA Technical Standards System: MIL-STD-461G endorsement
- NASA Technical Standards System: NASA-STD-7001 Payload Vibroacoustic Test Criteria
- ANSI Webstore: MIL-STD-810H
- CASRAI: A2LA accreditation and ISO/IEC 17025 scopes
- Open University: Introduction to planetary protection, cleanrooms
- Techsafety: Understanding ISO cleanroom classes (ISO 14644-1 table)
- Cleanroom Technology: What is ISO 8 cleanroom classification
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