Fragmentation Minimization

Prevention of on-orbit breakups recommended.

Minimize probability of accidental explosion (NRO) (0.0001 for NASA).

No credible failure modes shall exist to cause accidental explosions unless probability of failure mode is limited through design or operational procedures (DOD).

Passivation of all on-board energy sources (i.e., batteries, propellant, and pressurized systems) (NASA, USSPACECOM, DOD, FAA/FCC & DOT).

Intentional destruction shall not be a nominal process.

Passivation of potential fragmentation causes:

• residual propellant
• high pressure systems
• batteries

Intentional destruction is prohibited.

The probability of accidental explosion shall be kept to less than or equal to 0.0001.

Passivation shall be accomplished within one year of end-of-mission.

Intentional destruction of a space vehicle or any of its parts is prohibited.

The probability of accidental explosion from internal origin shall be kept to less than or equal to 10^-4 for the operational phase of the space vehicle.

All space vehicles shall be passivated and remain passivated after its operational phase (specific waivers are permitted).

Prevention of accidental explosion of space assets upon their active life ending by passivation of:

• residual propellant
• liquid and gas of the high pressure systems
• explosive devices
• flying wheels/ gyroscopes 
• batteries

except for those craft that are disposed of by controlled reentry or destruction.

Fragmentation Debris 
Minimization

Not Addressed since prevention is guideline.

Generation of debris by accidental explosion shall be minimized (DOD).

Limit the long-term risk to other space systems from intention break-ups by conducting such break-ups at an altitude (i.e., 90km for reentry process) such that:

a) debris larger than 1mm does not exceed 0.1m²-yr or 100 objects-yr.

b) no debris larger than 1mm will remain in orbit longer than a year.

c) the probability of debris larger than 1mm colliding with other assets does not exceed 10^-6 (NASA).

Not Addressed since prevention is standard.

Not Addressed since prevention is standard.

Not Addressed since prevention is standard.

Mitigate debris generation from spacecraft self-destruction:

• limiting the number of self-destructed device fragments in near-earth space
• self-destruct space vehicles just before reentry

Post-Mission 
Disposal

Remove mission terminated spacecraft from the useful regions.

GEO: raise perigee by 300km (ITU) and 245 – 435 km (IADC) and apogee by 250 km (ITU)

GTO: shorten lifetime of objects left in GTO (ITU)

Dispose of post-mission assets from high value regions (FAA/NOAA/FCC) by:

a) maneuvering LEO assets to an orbit (i.e., < 650km) inwhich atmospheric reentry will occur in 25 years due to natural causes (NASA, DOD, & USSPACECOM),

b) maneuvering LEO or GEO assets to a storage orbit with perigee above 2500km and apogee below 35,288 km (above LEO and below GEO) (NASA), 

c) directly retrieving LEO assets within 10 years (NASA & DOD),

d) maneuvering GEO assets to a storage orbit 300km above GEO (NASA & USSPACECOM) or 36,100km orbit (DOD)

e) maneuvering semi-synchronous assets with perigee above 19,900km and apogee below 20,500 km to a storage orbit with perigee above 2500km and apogee below 19,900km or to one with a perigee above 20,500km and apogee below 35,288 km (NASA),

f) maneuvering semi-synchronousassets \to a storage orbit above 500km higher (USSPACECOM),

g) maneuvering assets to a heliocentric orbit (DOD)

h) maneuvering assets to a storage orbit with perigee above 2000km and apogee below 19,700km or to one with a perigee above 20,700km and apogee below 35,300 km (DOD).

Remove post-mission spacecraft from high value regions by requiring that:

a) atmospheric reentry will occur in 25 years due to natural causes,

b) assets be maneuvered to a storage orbit above 1700 km (2500km if possible) and below 19,700km or to one above 20,500km and below 35,288 km,

c) assets be directly retrieved by STS,

d) spacecraft be maneuvered to a storage orbit above 200km above GEO.

Remove post-mission spacecraft from high value regions by:

a) atmospheric reentry will occur in 25 years due to natural causes,

b) maneuvering space systems to a storage orbit above 2000km and below 35,500 km,

c) maneuvering space systems to a storage orbit 235km above GEO.

Each project shall have a debris mitigation plan including a disposal plan for removal of post-mission space vehicles in accordance with the following:

a) The operator of a space vehicle shall perform maneuvers to limit orbital lifetime (periodic or permanent) to 25 years maximum via direct reentry, natural reentry, or disposal orbit placement,

b) GEO vehicles shall be re-orbited into a disposal orbit 235km above GEO.

Remove launch vehicles, ballistic missiles, and spacecraft upon service life termination by re-orbiting them to a burial region 200km above GEO or reducing their orbital lifetime.

Operational Debris Suppression

Limit the objects released during normal operations

Minimize size, quantity (FCC, NRO & DOD), and lifetime of LEO debris to:

a) a total area-time product of no larger than 0.1m2-yr and a object time product of no larger than 100 objects-yr for debris < 1mm (NASA)

b) an orbital lifetime of < 25 years for debris > 5mm in any dimension (DOD)

Minimize size, quantity (FCC, NRO & DOD), and lifetime of GEO debris to:

a) an orbital lifetime of < 25 with total area-time product of no larger than 0.1m2-yr and a object time product of no larger than 100 objects-yr for debris < 5cm (NASA)

b) an orbital lifetime of < 25 years for debris > 5mm in any dimension (DOD).

Minimize debris releases during normal operations.

Limit debris injected into orbit to 1 inert object per payload.

Minimize the production of debris and releases from:

·   Solid propellant motors

·   Pyrotechnical devices

·   Explosions

·   Aging materials

Limit debris injected into orbit by launch operations based on number of payloads per mission:

a) one element of debris for a single payload mission,

b) two (at most) elements of debris for a multiple payload mission.

 Payloads shall limit debris  

 generation by (although waivers  

 are permitted):

a) retaining released parts (i.e., deployment related devices),

b) released objects (even from material aging) are to be avoided (pyrotechnic release size limit is 10 microns).

Any sub-orbital space object shall not generate debris.

Limit fragment generation during partition and separation of payloads as well as the release of safety covers and springs.

Minimize the number of dangerous fragments from engines.

Material erosion shall be minimized.

Long spacecraft tethers shall retracted.

Collision Avoidance

Not addressed specifically yet.

Mitigate/minimize the potential for in-space collisions with other known objects (FAA/FCC, DOD & NRO) to:

a) < 0.001 probability for large objects

(NASA)

b) < 0.01 probability for small (1 cm- DOD) but with sufficient size to prevent mission disposal objects (NASA)

c) no physical contact between a launch vehicle or its components and its payload (DOT)

Avoid interference with spacecraft in the same orbital scheme.

Collision risk limit is program allocated.

Avoidance maneuvers are to be performed as necessary.

Not specifically addressed.

Collision risk of a space vehicle shall be known and orbital maneuvering provided for avoiding collisions. 

Sources:

[KATO 2001] & [ITU 1993]

[NOSMA 1995] & [Loftus 1999] & [DTIC 2001]

[KATO 2001]

[KATO 2001]

[Baccini 2002]

[RASA 2000]