Space Traffic Management: listening answers and explanations
An astronomy lecture on the need for a Space Traffic Management system to stop satellites and debris colliding in orbit. The lecturer explains what such a system would do, why it doesn't exist yet, and what solutions have been suggested.
One ten-gap note block, strictly in order. 31 comes in the definition. 'What are the problems in developing such a system?' starts 32-38. 'Let's consider now some of the solutions' starts 39-40. The problems come one after another with little pause, so keep your place in the list.
Answer key and self-check
Type what you wrote and hit mark. Hide the key first if you haven't done the part yet. Every question number jumps to its explanation.
How to attack this block: A dense academic lecture, but the notes follow it closely. Check the word form for each gap: an adjective after 'legal and', nouns after 'their' and 'a', an -ing form after 'systems for'. Several notes give you one half of a pair (legal, commercial), so the answer is the other half.
Question 31
Answer: technicalWhen the lecturer explains the aim of the system
What kind of ways, besides legal ones, would the system set up?
we'd need to have a set of legal measures. and we'd also have to develop the technical systems to enable us to prevent such accidents.
Question says → You hear
legal and ... wayslegal measures. and we'd also have to develop the technical systems
Why: The system needs legal measures and technical systems. 'Legal and ...' needs a matching adjective: technical.
The trap: Legal is already printed. Don't write a noun like 'systems': the gap is an adjective before 'ways'.
Question 32
Answer: cheapFirst problem, after 'What are the problems in developing such a system?'
Why are satellites more common now?
satellites are relatively cheap these days, compared with how they were in the past, meaning that more people can afford to put them into space.
Question says → You hear
quite ... and therefore more widespreadrelatively cheap … more people can afford to put them into space
Why: 'Relatively cheap' matches 'quite cheap', and because people can afford them, there are more of them.
The trap: Crowded comes a little later, but it describes space, not satellites.
Question 33
Answer: thousandsStraight after the point about cost
How many satellites are in a constellation?
people aren't just launching single satellites but whole constellations, consisting of thousands of them designed to work together.
Question says → You hear
constellations made up ofconstellations, consisting of thousands of them
Why: 'Consisting of' matches 'made up of', and the number is thousands. Write it as the word thousands.
The trap: Single comes just before, but that's the old way of launching. A digit like 1,000 doesn't match 'thousands of'.
Question 34
Answer: identification'one thing you may be surprised to learn'
What do satellites not have to send information to help with?
once it's out there, it doesn't have to send back any information to Earth to allow its identification.
Question says → You hear
not required to transmit informationdoesn't have to send back any information
Why: 'Doesn't have to send back' matches 'not required to transmit', and the purpose is identification. The gap needs a noun after 'their'.
The trap: Information is in the same sentence, but it's what isn't sent. The gap is what that information would help with.
Question 35
Answer: trackingWhen he compares satellites with planes
What kind of systems are there too few of?
at present we don't have anything like enough proper ways of tracking them.
Question says → You hear
There are few systems forwe don't have anything like enough proper ways of tracking them
Why: 'Not anything like enough' matches 'few', and the systems are for tracking. 'Systems for' needs an -ing form.
The trap: Colliding and safety are mentioned for planes just before. The satellite problem is about tracking them.
Question 36
Answer: militaryAfter 'some operators may be unwilling to share information'
For what reason, besides commercial ones, may operators keep satellites secret?
a satellite may be designed for military purposes, or it may have been launched for commercial reasons
Question says → You hear
used for ... or commercial reasonsfor military purposes, or … for commercial reasons
Why: The note pairs the gap with commercial, and the other purpose is military.
The trap: Commercial is printed already. Competitors come just after, but they're part of the commercial reason.
Question 37
Answer: location'And even if the operators are willing to provide it'
What detail about the object is hard to get at a given time?
Details are needed about the object itself, as well as about its location at a particular time
Question says → You hear
at a given timeat a particular time
Why: 'At a particular time' matches 'at a given time', and that's said about its location.
The trap: Size and speed (thousands of kilometres an hour) follow straight after and are why location is hard to pin down, but they aren't the detail in the note.
Question 38
Answer: predictionThe last problem, after 'We don't have any sensors'
What can scientists only make about where the satellite goes?
all that the scientists can do is to put forward a prediction concerning where the satellite is heading next.
Question says → You hear
can only make a ... about where the satellite will goall that the scientists can do is to put forward a prediction
Why: 'All that they can do' matches 'only', and 'put forward a prediction' matches 'make a prediction'. Noun after 'a'.
The trap: Sensors are mentioned, but they can't follow fast objects. Write the noun prediction, not the verb predict.
Question 39
Answer: databaseSecond solution, after common standards
Where should all the information be combined?
it needs to be put together so it can be used, and that will involve creating a single database on which it can be entered.
Question says → You hear
combined in oneput together … a single database
Why: 'Put together' matches 'combined' and 'single' matches 'one'.
The trap: Standards come just before, but they are the first solution, already in the notes.
Question 40
Answer: trustThe final solution, after 'To cope with this'
What must the coordinated system create in its users?
it's also essential that this system is one that establishes trust in the people that use it
Question says → You hear
create ... in its usersestablishes trust in the people that use it
Why: 'Establishes' matches 'create', and 'the people that use it' are its users. The gap is trust.
The trap: Coordinate is in the same sentence, but it's already in the note as 'coordinated system'.
The note needs a noun after 'their': identification. 'Information' is also in the sentence and sounds right, but it's already in the note as 'transmit information'.
The lecturer mentions the object itself, its location, its size and its speed. The note's 'at a given time' matches 'at a particular time', which goes with location.
Legal is printed in the note, so you need the second kind of measure. The answer comes after a sentence break: 'and we'd also have to develop the technical systems'.
Words from this recording worth keeping
orbit(Introduction)
the curved path an object follows around a planet
collisions(Introduction)
crashes between moving objects
constellations(Problems)
here, large groups of satellites working together
debris(Problems)
broken pieces left after something is destroyed
operators(Problems)
the companies or groups that run the satellites
sensors(Problems)
devices that detect and measure things
accessible(Solutions)
easy to reach or use
congestion(Solutions)
overcrowding that blocks movement
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The full Cambridge 18 Test 3 listening paper with the real audio: all four parts, played once, marked the moment you finish. Already done it? Take it again and listen for the traps this page showed you.
Cambridge IELTS 18, Test 3, Listening Part 4. The recording, transcript and questions belong to Cambridge University Press and are not reproduced here. We quote short extracts of the transcript only as evidence for our own commentary, and the answers are published for self-marking. Get the book for the full material, or sit the test on Langujet.
