Which packet fits the contact window?
You are the ground operations planner for Kestrel Survey, a fictional Earth observation mission.
The question
One confirmed contact ends before the science deadline. Its status reservation is fixed. Each payload packet must fit in one contact. The later contact starts after the science deadline.
| Whole data blocks | |
|---|---|
| First contact, total | 9 |
| First contact, reserved status | 2 |
| Science packet, due first | 5 |
| Context packet, may wait | 3 |
| Later contact, payload capacity | 6 |
The later contact’s payload capacity already excludes its status reservation.
“Choose what to send and explain what you would tell the science user if the plan changes.”
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A strong answer, step by step
Open each step in turn. This is one strong answer, not the only one.
Step 1: What capacity can you use?
What would you do here? Open the move you’d make.
Plan against all 9 blocks
Tempting, but it misses something. This double-counts the blocks already reserved for status.
Plan against 7 payload blocks
The strong move. This preserves the fixed 2-block reservation.
Use the later 6-block figure for both contacts
Tempting, but it misses something. The later contact has a different capacity and comes after the deadline.
See how a strong candidate says it
“The first contact has 7 blocks for payload data. Two of its 9 blocks are already reserved for status.”
Why it works: A gross contact estimate includes capacity that cannot carry either packet.
Step 2: Which packet goes first?
What would you do here? Open the move you’d make.
Send context, then attempt science
Tempting, but it misses something. A 5-block packet cannot fit in the 4 remaining blocks.
Split the science packet across contacts
Tempting, but it misses something. The case requires each packet to fit in one contact.
Use the first contact for the science packet
The strong move. It fits and meets the earlier deadline.
See how a strong candidate says it
“Send the 5-block science packet. That leaves 2 blocks, so the 3-block context packet waits.”
Why it works: The science packet is due before the next contact. If context goes first, only 4 blocks remain.
Step 3: What still fits?
The confirmed first contact can now carry 6 total blocks. The status reservation and the later contact are unchanged.
What would you do here? Open the move you’d make.
Keep status, plan context and seek an earlier science contact
The strong move. Context fits. A second confirmed window is needed to keep the science deadline.
Use one reserved status block to complete science
Tempting, but it misses something. The reservation is fixed in the case.
Send four blocks of science and report it as complete
Tempting, but it misses something. The remaining block is part of the required whole packet.
See how a strong candidate says it
“The reservation leaves 4 blocks. Context fits with 1 block spare, but science is 1 block short. I would ask the scheduling lead for another confirmed contact before the deadline and prepare a delay notice.”
Why it works: A shorter contact changes the feasible packet set. The status reservation still applies.
Step 4: What do you tell the user?
What would you do here? Open the move you’d make.
Confirm on-time science while scheduling checks
Tempting, but it misses something. The only confirmed earlier window cannot carry it.
Name the delay, fallback and scheduling owner
The strong move. The user gets a delivery expectation and the person who can change it.
Wait until the later packet arrives to explain the change
Tempting, but it misses something. The user would lose the chance to adjust to the delay.
See how a strong candidate says it
“The context packet fits now. Without an earlier confirmed contact, the later window can carry the 5-block science packet with 1 block spare, after the deadline.”
Why it works: A useful handoff distinguishes a confirmed plan from a possible recovery.
The answer, in short
- Decision
- Protect the reservation and report the science delay unless another contact is confirmed.
- Because
- The revised first contact can carry the context packet but cannot carry the whole science packet.
- What would change it
- A confirmed earlier contact with at least 5 payload blocks could keep the science deadline.
Common traps
- Count gross capacity as usable capacity.
- Promise a complete packet that cannot fit.
- Treat a possible alternate contact as booked.
Check your answer
- Did I subtract the fixed reservation?
- Did I prioritize the complete packet with the early deadline?
- Did I recalculate after the contact changed?
- Did I state the fallback and who can confirm a better slot?
Last reviewed Nov 11, 2026