Satcom Status Tracker

Two-Line Element sets make public satellite orbits portable, but they do not report a spacecraft's live position or health. Each TLE describes a fitted mean orbit at a reference time called the epoch. The record can support broad screening and later orbit propagation, while its usefulness for pointing and timing generally falls as the epoch gets older.

Freshness matters differently across missions. Atmospheric drag and maneuvers can move a low-orbiting object away from an old prediction quickly. A geostationary object may appear steadier, yet station keeping and drift still make current elements important. There is no universal age that guarantees a TLE is accurate enough; the acceptable age depends on the orbit, the operation, and the error margin.

Orbit labels such as low Earth orbit (LEO), medium Earth orbit (MEO), and the geostationary belt are useful for finding obvious mismatches. They remain broad categories. A record that looks like the expected orbit can still belong to the wrong catalog object, and an altitude estimate cannot replace propagation with an observer location.

A status check is therefore a triage step. It can narrow a catalog search, expose old elements, and attach public context to a NORAD catalog number. Before a real contact or link budget, confirm the object identity, obtain suitable current elements, propagate them with an appropriate model, and verify frequency, equipment, and operating constraints.

How to Use This Tool:

Choose the search and age policy before requesting records, then focus one retained row for detailed review.

1. Enter a satellite name or a 3 to 6 digit NORAD catalog number. Use Constellation preset only when its public keyword matches the group you intend to inspect.
2. Choose Freshness policy. Strict admits records up to 2 days old, Balanced up to 7 days, and Archive up to 14 days. A positive Stricter age cap can reduce that limit but cannot loosen it.
3. Turn on SatNOGS overlay when public operator and status context matters. Only active then keeps rows explicitly marked alive and not decayed; leave the overlay off when TLE evidence alone is enough.
4. Select Track satellite status, then choose the intended object in Satellite ledger. If every result disappears, loosen the age filter or status filters rather than assuming the catalog has no match.
5. Read Readiness review before using the selected TLE. Treat Freshness profile as a comparison of record ages, not as a prediction-error chart.

Interpreting Results:

Planning readiness is driven by TLE age. Up to 2 days is labeled Ready for first pass, more than 2 and up to 7 days is Use with caution, and more than 7 days is Refresh before use. These are local triage rules, not published accuracy guarantees.

Read Status separately from freshness. With the overlay off, TLE only means no public status request was made. With it on, an unavailable match stays unknown; it does not establish that the spacecraft is active, dead, or healthy.

The orbit class and estimated altitude are sanity checks. For pass times, azimuth, elevation, range, or Doppler, use the selected element set with SGP4 and the actual observer coordinates. Recheck the catalog number against the mission or operator source before committing equipment or airtime.

Technical Details:

The screening model reads inclination, eccentricity, and mean motion from TLE line 2. Epoch age is the observation time minus the record epoch in 86,400-second days. Mean motion supplies a circular-orbit estimate for period, semi-major axis, and altitude; it does not perform SGP4 propagation.

Formula Core

Mean motion n is given in revolutions per day. It is converted to angular speed before applying the circular form of Kepler's third law.

Here, ω is radians per second, μ is 398,600.4418 km³/s², a is semi-major axis in kilometres, R_E is the 6,371 km Earth-radius constant, h is approximate altitude in kilometres, and P is period in minutes. With 15.5 rev/day, the model gives about 92.90 minutes and 424 km. Displayed altitude is rounded to a whole kilometre; the retained chart age is rounded to six decimal places.

Lookup and Rule Core

Public records are limited by the selected age policy before status filters and result ordering are applied. Unknown and future epochs remain reviewable unless another filter removes them.

A positive custom age cap becomes the smaller of that value and the selected 2, 7, or 14 day policy, with a one-day floor. At most 40 returned records enter normalization. The optional stale-only view keeps Aging and Stale rows, while the active-only rule applies only when SatNOGS context is enabled.

Accuracy and Privacy Notes:

Live searches send the entered satellite name or catalog number to the public TLE API. Enabling the SatNOGS overlay also requests public context for returned NORAD numbers. The fixed example contacts neither service.

• The circular altitude estimate ignores eccentric position, perturbations, maneuvers, and observer geometry.
• Freshness bands and readiness labels are repository-authored review cues, not guarantees from CelesTrak, SatNOGS, the TLE provider, or a satellite operator.
• Auto-refresh repeats only a successful live lookup while the page remains open; use a conservative interval and stop repeated requests when a provider reports an error.

References:

• TLE API, Ivan Stanojevic.
• A New Way to Obtain GP Data, CelesTrak, updated 2026 June 23.
• Revisiting Spacetrack Report #3: Revision 3, AIAA and CelesTrak, 2006.
• SatNOGS DB API documentation, Libre Space Foundation.